Strange git fetch/pull after update

Question

I've update my Git and get some interesting errors like this one:

error: Server does not allow request for unadvertised object e7369c9b3741a15235ad6d960c026607cbff96ea

I have it on Git 2.21.0+ (2.20.1 works fine) on MacOS and Windows, errors only on submodule which is on Stash Server - main repo just has everything as a submodules.

Steps to reproduce:

1. git clone $main_repo
2. cd $main_repo
3. git remove origin
4. git add origin $main_repo
5. git fetch --all --prune - or pull, doesn't matter

Another strange thing: if I'll go to failed submodule and do same steps here - everything will be fine.

I don't understand is it a bug in Git or something wrong with my company Stash.

Any help to how to explore it deeper?