Description of problem:

The user successfully upgraded the ROSA hosted cluster from version 4.18.6 (candidate) to 4.19.0-ec.5. However, when attempting to update the machine pools to the corresponding version via the Machine Pools tab in the OCM UI, the following message was displayed:

"This machine pool cannot be updated because there isn't a migration path to version openshift-v4.19.0-ec.5-candidate."

Despite this UI restriction, the machine pool update was successfully completed using the ROSA CLI, indicating a discrepancy between the UI validation logic and the actual upgrade capability.
Reference screen recordings as below
Screen Recording 2025-06-05 at 12.55.44 PM.mov

Reference for ROSA CLI updates:

 % rosa upgrade machinepool workers-0 -c rosahcp-upgradetests5june 
? Are you sure you want to upgrade machine pool 'workers-0' to version '4.19.0-ec.5'? Yes
I: Upgrade successfully scheduled for the machine pool 'workers-0' on cluster 'rosahcp-upgradetests5june' 

Steps to Reproduce:

1. Navigate to the OCM UI (Staging Environment).
2. Install a ROSA HCP cluster with version 4.18.6 (candidate).
   Note: Set the update strategy to "Individual updates."
3. Once the cluster is fully provisioned and in a Ready state:
   1. Go to the Settings tab.
   2. Open the Update section.
4. Click the "Update" button.
5. In the "Update Cluster" modal:
   1. Select version 4.19.0-ec.5.
   2. Schedule the update.
6. Wait for the control plane upgrade to complete successfully.
7. Navigate to the Machine Pools tab.
8. Attempt to update the individual machine pools to version 4.19.0-ec.5.
9. Observe the behavior and check whether the UI allows or blocks the machine pool upgrade.

Actual results:

After a successful control plane upgrade to version 4.19.0-ec.5, each machine pool displays the following message in the OCM UI:

"This machine pool cannot be updated because there isn't a migration path to version openshift-v4.19.0-ec.5-candidate."

This message currently prevents users from upgrading machine pools via the OCM UI. However, the machine pools can still be successfully updated to the same version using the ROSA.

Expected results:
After a successful control plane upgrade, each machine pool should be able to update to the corresponding control plane version without any issues.