We have seen the reference delta not found error message while cloning a repository.

We created a minimal reproducible example: https://github.com/ZauberNerd/go-git-external-ref-thinpack

We already saw two other issues and a merged PR, mentioning this error message:

• PlainCloneContext fails with "reference delta not found" error when using aws codecommit repository  #336
• Failure to resolve deltas when PlainClone or Fetching from a new AWS CodeCommit repository #391

But those seem to only mention AWS CodeCommit (and we are on GHES) and even with #392 by @ga-paul-t merged, our reproducer is still able to reproduce the issue, therefore we are not sure, if it is the same issue or related in some other way.

Steps to reproduce:

1. git clone git@github.com:ZauberNerd/go-git-external-ref-thinpack.git
2. cd go-git-external-ref-thinpack/
3. git submodule update --init --recursive
4. go run main.go