Description of problem - Provide a detailed description of the issue encountered, including logs/command-output snippets and screenshots if the issue is observed in the UI:

mon_target_pg_per_osd flag value not updating in cephcluster after patching 

The OCP platform infrastructure and deployment type (AWS, Bare Metal, VMware, etc. Please clarify if it is platform agnostic deployment), (IPI/UPI):

IBM Power UPI

The ODF deployment type (Internal, External, Internal-Attached (LSO), Multicluster, DR, Provider, etc):

Internal-Attached (LSO)

The version of all relevant components (OCP, ODF, RHCS, ACM whichever is applicable):

OCP:  4.19.0-rc.0
ODF:  4.19.0-68.stable

Does this issue impact your ability to continue to work with the product?

yes

Is there any workaround available to the best of your knowledge?

No

Can this issue be reproduced? If so, please provide the hit rate

100%

Can this issue be reproduced from the UI?

NA

If this is a regression, please provide more details to justify this:

Steps to Reproduce:

1.Deploy ODF on new cluster

2. Create Storage-system & wait for Storage-system to be ready state.

3.apply patch command 

oc patch storagecluster ocs-storagecluster -n openshift-storage --type merge --patch '{
"spec": {
"managedResources": {
"cephCluster": {
"cephConfig": {
"global": {
"mon_target_pg_per_osd": "100"
}
}
}
}
}
}' 

The exact date and time when the issue was observed, including timezone details:

19-05-2025:11:30 AM IST

Actual results:

mon_target_pg_per_osd values not changed change in cephcluster .

[root@veera-419-a10e-bastion-0 ~]# oc get cephcluster -o yaml
apiVersion: v1
items:
- apiVersion: ceph.rook.io/v1
  kind: CephCluster
  metadata:
    creationTimestamp: "2025-05-15T16:02:40Z"
    finalizers:
    - cephcluster.ceph.rook.io
    generation: 1
    labels:
      app: ocs-storagecluster
    name: ocs-storagecluster-cephcluster
    namespace: openshift-storage
    ownerReferences:
    - apiVersion: ocs.openshift.io/v1
      blockOwnerDeletion: true
      controller: true
      kind: StorageCluster
      name: ocs-storagecluster
      uid: dd4198ad-e37a-4994-8444-ab6d243aceb3
    resourceVersion: "2749405"
    uid: 9168d1f8-15b6-458b-a016-15b99cfd763e
  spec:
    cephConfig:
      global:
        mon_max_pg_per_osd: "1000"
        mon_target_pg_per_osd: "400"
 

Expected results:

mon_target_pg_per_osd values should be change in cephcluster .

Logs collected and log location:

Additional info: