SIDB standby stuck in Unhealthy

[andbos]

My SIDB standby instance is stuck in Unhealthy even though the instance is running OK and Dataguard is running OK.
I tried /home/oracle/shutDown.sh immediate followed with /home/oracle/startUp.sh, worked as such but standby pod is never ready.

$ kubectl -n oracle-database get pods
NAME                   READY   STATUS    RESTARTS      AGE
cnfdb-dgbroker-h881r   1/1     Running   0             22h
cnfdb11-czmxg          1/1     Running   1 (28h ago)   28h
cnfdb12-7e3mo          0/1     Running   0             9m43s

$ kubectl -n oracle-database get sidb
NAME      EDITION      STATUS      ROLE               VERSION       CONNECT STR                    TCPS CONNECT STR   OEM EXPRESS URL
cnfdb11   Enterprise   Healthy     PRIMARY            19.29.0.0.0   10.240.222.19:1521/NCNFDB11    Unavailable        https://10.12.86.125:5500/em
cnfdb12   Enterprise   Unhealthy   PHYSICAL_STANDBY   19.29.0.0.0   10.12.86.125:1521/NCNFDB12     Unavailable        https://10.12.86.125:5500/em

$ kubectl -n oracle-database get sidb cnfdb12 -o json | jq '.status'
{
  "archiveLog": "true",
  "clusterConnectString": "cnfdb12-ext.oracle-database:1521/NCNFDB12",
  "conditions": [
    {
      "lastTransitionTime": "2026-01-15T09:45:27Z",
      "message": "command terminated with exit code 1",
      "observedGeneration": 1,
      "reason": "LastReconcileCycleFailed",
      "status": "True",
      "type": "ReconcileError"
    },
    {
      "lastTransitionTime": "2026-01-15T09:45:37Z",
      "message": "no reconcile errors",
      "observedGeneration": 1,
      "reason": "LastReconcileCycleCompleted",
      "status": "True",
      "type": "ReconcileComplete"
    },
    {
      "lastTransitionTime": "2026-01-27T13:17:21Z",
      "message": "no reconcile errors",
      "observedGeneration": 1,
      "reason": "LastReconcileCycleQueued",
      "status": "True",
      "type": "ReconcileQueued"
    }
  ],
  "connectString": "10.12.86.125:1521/NCNFDB12",
  "createdAs": "standby",
  "datafilesCreated": "true",
  "datafilesPatched": "false",
  "dgBroker": "cnfdb-dgbroker",
  "edition": "Enterprise",
  "flashBack": "true",
  "forceLog": "true",
  "initParams": {
    "cpuCount": 8,
    "pgaAggregateTarget": 1599,
    "processes": 640,
    "sgaTarget": 4800
  },
  "isTcpsEnabled": false,
  "oemExpressUrl": "https://10.12.86.125:5500/em",
  "pdbConnectString": "10.12.86.125:1521/ORCLPDB1",
  "pdbName": "ORCLPDB1",
  "persistence": {
    "accessMode": "ReadWriteOnce",
    "size": "300Gi",
    "storageClass": "csi-sc-cinderplugin"
  },
  "primaryDatabase": "cnfdb11",
  "releaseUpdate": "19.29.0.0.0",
  "replicas": 1,
  "role": "PHYSICAL_STANDBY",
  "sid": "NCNFDB12",
  "status": "Unhealthy",
  "tcpsConnectString": "Unavailable",
  "tcpsPdbConnectString": "Unavailable",
  "tcpsTlsSecret": ""
}

$ kubectl -n oracle-database get dgbroker
NAME             PRIMARY    STANDBYS   PROTECTION MODE   CONNECT STR                   STATUS    FSFO
cnfdb-dgbroker   NCNFDB11   NCNFDB12   MaxAvailability   10.12.86.110:1521/DATAGUARD   Healthy   true

$ kubectl -n oracle-database exec -it cnfdb11-czmxg -- /bin/bash
bash-5.1$ dgmgrl / as sysdba
DGMGRL for Linux: Release 19.0.0.0.0 - Production on Tue Jan 27 13:08:56 2026
Version 19.29.0.0.0

Copyright (c) 1982, 2019, Oracle and/or its affiliates.  All rights reserved.

Welcome to DGMGRL, type "help" for information.
Connected to "NCNFDB11"
Connected as SYSDBA.
DGMGRL> show configuration

Configuration - dg_config

  Protection Mode: MaxAvailability
  Members:
  ncnfdb11 - Primary database
    ncnfdb12 - (*) Physical standby database

Fast-Start Failover: Enabled in Zero Data Loss Mode

Configuration Status:
SUCCESS   (status updated 40 seconds ago)

The standby database seems however to be 100% healthy:

$ kubectl -n oracle-database exec -it cnfdb12-7e3mo -- /bin/bash
bash-5.1$ dgmgrl / as sysdba
SQL> SELECT RECOVERY_MODE FROM V$ARCHIVE_DEST_STATUS WHERE DEST_ID=1;

RECOVERY_MODE
----------------------------------
MANAGED REAL TIME APPLY

SQL> SELECT name, open_mode, database_role, switchover_status FROM v$database;

NAME      OPEN_MODE            DATABASE_ROLE    SWITCHOVER_STATUS
--------- -------------------- ---------------- --------------------
NCNFDB11  READ ONLY WITH APPLY PHYSICAL STANDBY NOT ALLOWED

SQL> SELECT NAME, VALUE, DATUM_TIME FROM V$DATAGUARD_STATS WHERE NAME LIKE '%lag%';

NAME
--------------------------------
VALUE
----------------------------------------------------------------
DATUM_TIME
------------------------------
transport lag
+00 00:00:00
01/27/2026 13:06:03

apply lag
+00 00:00:00
01/27/2026 13:06:03

NAME
--------------------------------
VALUE
----------------------------------------------------------------
DATUM_TIME
------------------------------

SQL> SELECT PROCESS, STATUS, SEQUENCE# FROM V$MANAGED_STANDBY;

PROCESS   STATUS        SEQUENCE#
--------- ------------ ----------
ARCH      CONNECTED             0
DGRD      ALLOCATED             0
DGRD      ALLOCATED             0
ARCH      CLOSING             190
ARCH      CLOSING             192
ARCH      CLOSING             193
RFS       IDLE                  0
RFS       IDLE                  0
RFS       IDLE                194
MRP0      APPLYING_LOG        194
RFS       IDLE                  0

11 rows selected.

SQL> SELECT THREAD#, LOW_SEQUENCE#, HIGH_SEQUENCE# FROM V$ARCHIVE_GAP;

no rows selected