diff --git a/apps/node-agent/monitor/journal_events.py b/apps/node-agent/monitor/journal_events.py
index 62f1f88..26fc006 100644
--- a/apps/node-agent/monitor/journal_events.py
+++ b/apps/node-agent/monitor/journal_events.py
@@ -53,13 +53,13 @@ def watch(collector):
         "+",
         "_SYSTEMD_UNIT=mission-core-node-monitor.service",
         "+",
-        "_SYSTEMD_UNIT=postgresql@16-ndc-monitor.service",
+        "_SYSTEMD_UNIT=postgresql@16-ndcmonitor.service",
     ]
     for unit in (
         "mission-core-node.service",
         "mission-core-k1.service",
         "mission-core-node-monitor.service",
-        "postgresql@16-ndc-monitor.service",
+        "postgresql@16-ndcmonitor.service",
     ):
         args.extend(["+", "UNIT=" + unit])
     while not collector.stop.is_set():
diff --git a/apps/node-agent/monitor/linux_metrics.py b/apps/node-agent/monitor/linux_metrics.py
index d3efecb..16a0c41 100644
--- a/apps/node-agent/monitor/linux_metrics.py
+++ b/apps/node-agent/monitor/linux_metrics.py
@@ -296,7 +296,7 @@ class LinuxMetrics:
             )
         groups = self.paths("sys/fs/cgroup/system.slice/mission-core*.service")
         groups += self.paths(
-            "sys/fs/cgroup/system.slice/system-postgresql.slice/postgresql@16-ndc-monitor.service"
+            "sys/fs/cgroup/system.slice/system-postgresql.slice/postgresql@16-ndcmonitor.service"
         )
         groups += self.paths(
             "sys/fs/cgroup/user.slice/user-*.slice/user@*.service/app.slice/app-gnome-org.nodedc.MissionCoreNode-*.scope"
diff --git a/apps/node-agent/packaging/build_deb.py b/apps/node-agent/packaging/build_deb.py
index 8b5c567..05c894f 100644
--- a/apps/node-agent/packaging/build_deb.py
+++ b/apps/node-agent/packaging/build_deb.py
@@ -11,7 +11,7 @@ import sys
 
 
 ROOT = Path(__file__).resolve().parents[1]
-VERSION = "0.8.15"
+VERSION = "0.8.16"
 sys.path.insert(0, str(ROOT.parents[1] / "scripts/packaging"))
 from debian import package
 
diff --git a/apps/node-agent/packaging/install-monitor-release b/apps/node-agent/packaging/install-monitor-release
index 96d5da8..fbeac0c 100644
--- a/apps/node-agent/packaging/install-monitor-release
+++ b/apps/node-agent/packaging/install-monitor-release
@@ -30,11 +30,27 @@ fi
 DEBIAN_FRONTEND=noninteractive apt-get install -y --no-remove \
   "$mc_release_dir/timescaledb-2-loader-postgresql-16_2.29.2~ubuntu24.04-1615_amd64.deb" \
   "$mc_release_dir/timescaledb-2-oss-postgresql-16_2.29.2~ubuntu24.04-1615_amd64.deb" \
-  "$mc_release_dir/mission-core-node_0.8.15_amd64.deb" \
+  "$mc_release_dir/mission-core-node_0.8.16_amd64.deb" \
   "$mc_release_dir/mission-core-xgrids-k1_0.1.14_amd64.deb"
 systemctl is-active --quiet mission-core-node.service
 systemctl is-active --quiet mission-core-k1.service
-systemctl is-active --quiet postgresql@16-ndc-monitor.service
+runuser -u mission-core-node -- /usr/bin/python3 - <<'K1CHECK'
+import http.client,json,socket,time
+deadline=time.monotonic()+20
+while True:
+    c=http.client.HTTPConnection('k1',timeout=3)
+    c.sock=socket.socket(socket.AF_UNIX);c.sock.settimeout(3)
+    try:
+        c.sock.connect('/run/mission-core-k1/driver.sock')
+        c.request('GET','/status');r=c.getresponse();v=json.load(r)
+        if r.status==200 and v.get('available') is True:break
+    except (OSError, ValueError, http.client.HTTPException):pass
+    finally:c.close()
+    if time.monotonic()>deadline:raise SystemExit('K1 enrollment service did not become ready')
+    time.sleep(1)
+print('K1 enrollment service: ready')
+K1CHECK
+systemctl is-active --quiet postgresql@16-ndcmonitor.service
 systemctl is-active --quiet mission-core-node-monitor.service
 runuser -u mission-core-monitor -- /usr/bin/python3 - <<'PY'
 import http.client,json,socket,time
@@ -53,4 +69,4 @@ while True:
     time.sleep(1)
 print('Local telemetry: ready')
 PY
-printf '%s\n' 'Mission Core Node R18: package and local archive checks passed.'
+printf '%s\n' 'Mission Core Node R19: package and local archive checks passed.'
diff --git a/apps/node-agent/packaging/mission-core-node-monitor.service b/apps/node-agent/packaging/mission-core-node-monitor.service
index eb6e80b..6cc553a 100644
--- a/apps/node-agent/packaging/mission-core-node-monitor.service
+++ b/apps/node-agent/packaging/mission-core-node-monitor.service
@@ -1,7 +1,7 @@
 [Unit]
 Description=Mission Core onboard system telemetry collector
-After=postgresql@16-ndc-monitor.service
-Wants=postgresql@16-ndc-monitor.service
+After=postgresql@16-ndcmonitor.service
+Wants=postgresql@16-ndcmonitor.service
 
 [Service]
 Type=simple
diff --git a/apps/node-agent/packaging/postinst b/apps/node-agent/packaging/postinst
index ef9ce64..0d8a505 100644
--- a/apps/node-agent/packaging/postinst
+++ b/apps/node-agent/packaging/postinst
@@ -23,7 +23,15 @@ case "$1" in
         fi
         rm -f /run/mission-core-node-k1-upgrade-active
       fi
-      /usr/lib/mission-core-node/setup-monitor
+      # A diagnostic service must not leave Node half-configured and prevent
+      # dpkg from configuring the separately packaged acquisition plugin.
+      if /usr/lib/mission-core-node/setup-monitor; then
+        rm -f /run/mission-core-monitor-setup-failed
+      else
+        mc_monitor_result=$?
+        printf '%s\n' "$mc_monitor_result" > /run/mission-core-monitor-setup-failed
+        echo "Mission Core Node: monitoring setup failed; device services remain independent." >&2
+      fi
     fi
     ;;
 esac
diff --git a/apps/node-agent/packaging/prerm b/apps/node-agent/packaging/prerm
index ba758fd..e304727 100644
--- a/apps/node-agent/packaging/prerm
+++ b/apps/node-agent/packaging/prerm
@@ -54,8 +54,8 @@ case "$1" in
       systemctl disable mission-core-node.service
       systemctl stop mission-core-node-monitor.service
       systemctl disable mission-core-node-monitor.service
-      systemctl stop postgresql@16-ndc-monitor.service
-      systemctl disable postgresql@16-ndc-monitor.service
+      systemctl stop postgresql@16-ndcmonitor.service
+      systemctl disable postgresql@16-ndcmonitor.service
     fi
     ;;
 esac
diff --git a/apps/node-agent/packaging/setup-monitor b/apps/node-agent/packaging/setup-monitor
index ed9c466..9bf71a3 100644
--- a/apps/node-agent/packaging/setup-monitor
+++ b/apps/node-agent/packaging/setup-monitor
@@ -9,11 +9,22 @@ install -d -m 0750 -o mission-core-monitor -g mission-core-node /var/lib/mission
 install -d -m 0755 -o postgres -g postgres /run/mission-core-monitor-db
 install -d -m 0755 /etc/tmpfiles.d
 printf '%s\n' 'd /run/mission-core-monitor-db 0755 postgres postgres -' > /etc/tmpfiles.d/mission-core-monitor.conf
-if [ ! -d /etc/postgresql/16/ndc-monitor ]; then
- pg_createcluster 16 ndc-monitor --port=5433 --socketdir=/run/mission-core-monitor-db --datadir=/var/lib/mission-core-monitor-db --start-conf=auto -- --auth-local=peer --auth-host=reject
+# R18 used a dash, which the PostgreSQL systemd template expands as a slash.
+# Rename only our exact cluster. pg_renamecluster preserves this custom data
+# directory, updates its configuration paths, and retains all database files.
+if [ -d /etc/postgresql/16/ndc-monitor ]; then
+ test ! -d /etc/postgresql/16/ndcmonitor
+ test "$(pg_conftool -s 16 ndc-monitor show data_directory)" = /var/lib/mission-core-monitor-db
+ test "$(pg_conftool -s 16 ndc-monitor show port)" = 5433
+ pg_renamecluster 16 ndc-monitor ndcmonitor
 fi
-install -d -m 0755 /etc/postgresql/16/ndc-monitor/conf.d
-cat > /etc/postgresql/16/ndc-monitor/conf.d/60-mission-core-monitor.conf <<'CONF'
+if [ ! -d /etc/postgresql/16/ndcmonitor ]; then
+ pg_createcluster 16 ndcmonitor --port=5433 --socketdir=/run/mission-core-monitor-db --datadir=/var/lib/mission-core-monitor-db --start-conf=auto -- --auth-local=peer --auth-host=reject
+fi
+test "$(pg_conftool -s 16 ndcmonitor show data_directory)" = /var/lib/mission-core-monitor-db
+test "$(pg_conftool -s 16 ndcmonitor show port)" = 5433
+install -d -m 0755 /etc/postgresql/16/ndcmonitor/conf.d
+cat > /etc/postgresql/16/ndcmonitor/conf.d/60-mission-core-monitor.conf <<'CONF'
 listen_addresses = ''
 unix_socket_directories = '/run/mission-core-monitor-db'
 shared_preload_libraries = 'timescaledb'
@@ -32,8 +43,8 @@ statement_timeout = '5s'
 log_statement = 'none'
 log_min_error_statement = 'panic'
 CONF
-install -d -m 0755 /etc/systemd/system/postgresql@16-ndc-monitor.service.d
-cat > /etc/systemd/system/postgresql@16-ndc-monitor.service.d/60-mission-core-monitor.conf <<'CONF'
+install -d -m 0755 /etc/systemd/system/postgresql@16-ndcmonitor.service.d
+cat > /etc/systemd/system/postgresql@16-ndcmonitor.service.d/60-mission-core-monitor.conf <<'CONF'
 [Service]
 ExecStartPre=+/usr/bin/install -d -m 0755 -o postgres -g postgres /run/mission-core-monitor-db
 MemoryHigh=256M
@@ -43,7 +54,7 @@ TasksMax=32
 Nice=10
 CONF
 systemctl daemon-reload
-systemctl restart postgresql@16-ndc-monitor.service
+systemctl restart postgresql@16-ndcmonitor.service
 runuser -u postgres -- psql -X -v ON_ERROR_STOP=1 -h /run/mission-core-monitor-db -p 5433 -d postgres <<'SQL'
 SELECT 'CREATE ROLE "mission-core-monitor" LOGIN NOSUPERUSER NOCREATEDB NOCREATEROLE' WHERE NOT EXISTS(SELECT FROM pg_roles WHERE rolname='mission-core-monitor') \gexec
 SELECT 'CREATE DATABASE mission_core_monitor OWNER "mission-core-monitor"' WHERE NOT EXISTS(SELECT FROM pg_database WHERE datname='mission_core_monitor') \gexec
diff --git a/docs/audits/2026-09-08-node-runtime-and-system-monitor.md b/docs/audits/2026-09-08-node-runtime-and-system-monitor.md
index bb576ef..e5e6ae6 100644
--- a/docs/audits/2026-09-08-node-runtime-and-system-monitor.md
+++ b/docs/audits/2026-09-08-node-runtime-and-system-monitor.md
@@ -135,3 +135,30 @@ Pending owner sudo: installed service/version checks, socket-only cluster,
 archive growth, measured collector overhead, Core durable ACK/backfill, and
 browser QA with real telemetry. A new physical K1 scan and critical scenarios
 remain operator qualification, not an automatically exercised acceptance step.
+
+
+## R18 installation regression and R19 correction
+
+Owner resumed 08.09.2026. R18 install-result is 100, Node 0.8.15 half-configured,
+K1 0.1.14 unpacked, Node active but K1 stopped. The exact systemd assertion is
+`/etc/postgresql/16/ndc/monitor/postgresql.conf` missing: the installed Debian
+PostgreSQL template expands `%I` by replacing instance dashes with path separators.
+The cluster name `ndc-monitor` caused the path mismatch. This is a packaging
+error, independent of the powered-off K1. Native R18 archive qualification used
+a temporary directly started PostgreSQL process and did not cover this systemd
+instance contract; the old lifecycle stub also accepted every systemctl command.
+
+R19 / Node 0.8.16 uses cluster `ndcmonitor`. A guarded `pg_renamecluster` migrates
+only the predecessor with exact custom data directory and port 5433, preserving
+data and updating configuration paths. It refuses a conflicting destination or
+foreign data path. All service references/cgroup metrics/journal filters agree.
+Monitoring bootstrap failure is now diagnostic: Node postinst records it and
+returns success so dpkg can configure the separate K1 plugin. The release
+installer still fails its monitoring acceptance if the archive is unavailable;
+it also requires K1's read-only status endpoint to answer available=true.
+
+Regression tests execute fresh setup, repeated R18 migration, foreign-cluster
+refusal, and both successful/failing monitor setup across Node/K1 lifecycle
+states. They implement the actual Debian `%I` assertion rule, so the previous
+hyphenated name fails. Real root-installed service and archived samples remain
+an explicit post-install gate, never inferred from stub or fixture success.
diff --git a/tests/test_node_k1_package_lifecycle.py b/tests/test_node_k1_package_lifecycle.py
index 2c7134d..eff9159 100644
--- a/tests/test_node_k1_package_lifecycle.py
+++ b/tests/test_node_k1_package_lifecycle.py
@@ -9,9 +9,10 @@ import pytest
 PACKAGING = Path(__file__).resolve().parents[1] / "apps/node-agent/packaging"
 
 
+@pytest.mark.parametrize("monitor_fails", [False, True])
 @pytest.mark.parametrize("active,configured", [(True, True), (False, True), (True, False)])
 def test_node_update_restores_only_previously_running_configured_plugin(
-    tmp_path, active, configured,
+    tmp_path, active, configured, monitor_fails,
 ):
     binary = tmp_path / "bin"
     binary.mkdir()
@@ -34,7 +35,7 @@ case "$1" in
 esac
 ''')
     (binary / "getent").write_text("#!/bin/sh\nexit 0\n")
-    (binary / "setup-monitor").write_text("#!/bin/sh\nprintf '%s\\n' monitor-setup >> \"$TEST_EVENTS\"\n")
+    (binary / "setup-monitor").write_text("#!/bin/sh\nprintf '%s\\n' monitor-setup >> \"$TEST_EVENTS\"\nexit " + ("1" if monitor_fails else "0") + "\n")
     (binary / "dpkg-query").write_text(
         "#!/bin/sh\necho 'install ok " + ("installed" if configured else "unpacked") + "'\n"
     )
@@ -56,3 +57,5 @@ esac
     assert ("start mission-core-k1.service" in calls) is (active and configured)
     assert state.exists() is (active and configured)
     assert not (run / "mission-core-node-k1-upgrade-active").exists()
+
+    assert (run / "mission-core-monitor-setup-failed").exists() is monitor_fails
diff --git a/tests/test_node_monitor_package.py b/tests/test_node_monitor_package.py
new file mode 100644
index 0000000..8ae55fc
--- /dev/null
+++ b/tests/test_node_monitor_package.py
@@ -0,0 +1,74 @@
+"""Exercise the monitor bootstrap against PostgreSQL's systemd path contract."""
+
+import os
+import subprocess
+from pathlib import Path
+
+import pytest
+
+SETUP = Path(__file__).resolve().parents[1] / "apps/node-agent/packaging/setup-monitor"
+
+
+@pytest.mark.parametrize("legacy,foreign", [(False, False), (True, False), (True, True)])
+def test_cluster_path_and_r18_migration_are_repeatable(tmp_path, legacy, foreign):
+    binary = tmp_path / "bin"
+    binary.mkdir()
+    conf = tmp_path / "etc/postgresql/16"
+    conf.mkdir(parents=True)
+    if legacy:
+        (conf / "ndc-monitor").mkdir()
+        (conf / "ndc-monitor/postgresql.conf").write_text("preserved R18 configuration")
+    driver = binary / "driver"
+    driver.write_text("""#!/usr/bin/env python3
+import os,sys,pathlib
+root=pathlib.Path(os.environ['TEST_ROOT']);name=pathlib.Path(sys.argv[0]).name;args=sys.argv[1:]
+with (root/'events').open('a') as log:log.write(name+' '+ ' '.join(args)+'\\n')
+conf=root/'etc/postgresql/16'
+if name=='id':print(0)
+elif name=='install':pathlib.Path(args[-1]).mkdir(parents=True,exist_ok=True)
+elif name=='pg_conftool':
+ print(os.environ.get('TEST_DATA_ROOT',str(root/'var/lib/mission-core-monitor-db')) if args[-1]=='data_directory' else '5433')
+elif name=='pg_createcluster':
+ (conf/args[1]).mkdir();(conf/args[1]/'postgresql.conf').write_text('new database')
+elif name=='pg_renamecluster':
+ (conf/args[1]).rename(conf/args[2])
+elif name=='systemctl' and args[0]=='restart' and args[1].startswith('postgresql@'):
+ # Exact installed Debian template: AssertPathExists=/etc/postgresql/%I/postgresql.conf.
+ instance=args[1].split('@')[1].removesuffix('.service')
+ assert (root/'etc/postgresql'/instance.replace('-','/')/'postgresql.conf').is_file()
+""")
+    driver.chmod(0o700)
+    for name in [
+        "id",
+        "getent",
+        "install",
+        "pg_conftool",
+        "pg_createcluster",
+        "pg_renamecluster",
+        "systemctl",
+        "runuser",
+    ]:
+        (binary / name).symlink_to(driver)
+    script = tmp_path / "setup"
+    text = SETUP.read_text()
+    for path in ["/etc/", "/var/lib/", "/run/"]:
+        text = text.replace(path, str(tmp_path / path.lstrip("/")) + "/")
+    script.write_text(text)
+    env = dict(
+        os.environ, PATH=str(binary) + os.pathsep + os.environ["PATH"], TEST_ROOT=str(tmp_path)
+    )
+    if foreign:
+        env["TEST_DATA_ROOT"] = "/unrelated/database"
+        result = subprocess.run(["/bin/sh", str(script)], env=env, capture_output=True)
+        assert result.returncode != 0
+        assert (conf / "ndc-monitor/postgresql.conf").is_file()
+        assert "pg_renamecluster" not in (tmp_path / "events").read_text()
+        return
+    for _ in range(2):
+        subprocess.run(["/bin/sh", str(script)], env=env, check=True, capture_output=True)
+    calls = (tmp_path / "events").read_text()
+    assert calls.count("pg_renamecluster 16 ndc-monitor ndcmonitor") == int(legacy)
+    assert calls.count("pg_createcluster 16 ndcmonitor") == int(not legacy)
+    assert not (conf / "ndc-monitor").exists()
+    if legacy:
+        assert (conf / "ndcmonitor/postgresql.conf").read_text() == "preserved R18 configuration"