Gitlab repo export error “fatal: bad object [FILTERED]

I am trying to move a repository I inherited from a self hosted gitlab, to another self hosted gitlab.

I have exported multiple repo’s to the new gitlab however one repository is giving me this error whenever I try to export the repo.

Project XXXXX couldn’t be exported.

The errors we encountered were:
13:create bundle: exit status 128: stderr: “fatal: bad object [FILTERED]

I cannot figure out what this is. I have done multiple manual housekeeping and pruning of unreachable objects. I have removed nearly all old stale branches. I cannot figure out what this error is.

All my normal git actions on this repo work for pushing/pulling/branching etc but this export is a problem. I have read online that I should look into further repo cleaning tools however without the ability to back it up via export I cannot use those tools.

When I forked the repo and tried to export it, then it worked so I have to assume there is some bad object somewhere in the ref’s.

I also got a look at the exports.log which shows the same error and no more information.

What is the problem, why cant I export this? What object is bad?