Shoot migration fails while using server group

[Wieneo]

How to categorize this issue?
/area control-plane-migration
/kind bug
/platform openstack

What happened:
While trying to migrate a shoot, which is using anti affinity for its worker nodes, between 2 seeds the migration got stuck with the following error:
Error restoring Worker: failed to generate the machine deployments: server group is required for pool "general", but no server group dependency found

What you expected to happen:
Migration succeedes

How to reproduce it (as minimally and precisely as possible):

• Create shoot on OpenStack
• Add anti-affinity to worker nodes
• Migrate shoot to another seed

Environment:

• Gardener version (if relevant): 1.71.5
• Extension version: v1.35.1
• Kubernetes version (use kubectl version):

Client Version: version.Info{Major:"1", Minor:"27", GitVersion:"v1.27.3", GitCommit:"25b4e43193bcda6c7328a6d147b1fb73a33f1598", GitTreeState:"clean", BuildDate:"2023-06-14T09:47:38Z", GoVersion:"go1.20.5", Compiler:"gc", Platform:"darwin/arm64"}
Kustomize Version: v5.0.1
Server Version: version.Info{Major:"1", Minor:"25", GitVersion:"v1.25.10", GitCommit:"e770bdbb87cccdc2daa790ecd69f40cf4df3cc9d", GitTreeState:"clean", BuildDate:"2023-05-17T14:06:35Z", GoVersion:"go1.19.9", Compiler:"gc", Platform:"linux/amd64"}