rancher: Restoring rancher from a backup on a migrated rancher server fails with the error unable to create new content in namespace cluster-fleet-default-anupamapostbkp because it is being terminated error restoring

Rancher Server Setup

• Rancher version: v2.6.0-rc8
• Installation option (Docker install/Helm Chart): Helm
  • If Helm Chart, Kubernetes Info: RKE1 Cluster Type (RKE1, RKE2, k3s, EKS, etc): Node Setup: 3 nodes all roles Version: v1.21.4
• Proxy/Cert Details: Self-signed

Information about the Cluster

• Kubernetes version:
• Cluster Type (Local/Downstream): Downstream node driver rke1 and rke2 clusters
  • If downstream, what type of cluster? (Custom/Imported or specify provider for Hosted/Infrastructure Provider):

Describe the bug Restoring rancher server from the backup that is created on a rancher server that is migrated to a new rke cluster.

To Reproduce

• On rancher server created an rke1 and rke2 node driver clusters [3 worker, 1 etcd, 1 cp ] in each cluster
• Installed backup charts in the local cluster. version 2.0.0+up2.0.0-rc11
• from continuous delivery, created a git repo - fleet1, url https://github.com/rancher/fleet-examples , path: multi-cluster/helm
• Took a backup of the rancher server - bkp1
• Created another git repo - fleet2 [url: https://github.com/rancher/fleet-examples , path: single-cluster/helm
• Created another backup - bkp2 [will reuse after migration]
• Created a new rke1 cluster and installed the rancher backup charts version 2.0.0+up2.0.0-rc11.
• Restored the backup on the new rke cluster and migrated rancher to the new rke cluster. ref:https://rancher.com/docs/rancher/v2.x/en/backups/v2.5/migrating-rancher/
• All clusters come up fine. verify no errors in fleet logs in the downstream clusters and the clusters in continuous delivery are all up and active.
• Create a new rke2 cluster on this new rancher server.
• Take a backup bkp3 once the cluster is up.
• Perform restore from the backup - bkp2 [from the steps above]
• All clusters come up fine. verify no errors in fleet logs in the downstream clusters and the clusters in continuous delivery are all up and active.
• Perform another restore with bkp3.

Result

• restore fails with the errors seen in the logs continuously in the backup resource rancher-backup-xxx.

- rancher server retries multiple times, after sometime the rancher server comes up and the cluster created after migration in the new rke cluster is stuck in `Wait Check-In` state on the cluster.

Expected Result Restore should be successful and no errors should be seen. Downstream clusters should come up active.

Additional Info:

Issue is seen for both rke1 and rke2 downstream clusters:

Related: https://github.com/rancher/rancher/issues/33954

SURE-5358