Git errors after changing RepoURL in ApplicationSet/Application

[bugspencor]

Our Git was migrated so I changed the RepoURL of the ApplicationSet. ArgoCD shows the correct RepoURL in the Applications and also sees the new commits in the new repo, but when syncing the app I get error messages:

Unable to load data: error acquiring repo lock: failed to initialize repository resources: rpc error: code = Internal desc = Failed to checkout revision d290...21a1: git fetch origin d290...21a1 --tags --force --prune failed exit status 1: error: Server does not allow request for unadvertised object d290...21a1

Only when pushing the changes to the old git repo the sync works. So somewhere ArgoCD seems to still use the old repository. I already hard refreshed the Applications and deleted all ArgoCD pods (in no specific order though).

I did not find something in the documentation how to change the RepoURL. Is it supported and are there any specific steps to do?