Fsync error: Bad file descriptor

I’m having this problem with our local (self hosted) installation of Gitea: since a couple of days, we’re getting this error on push:

remote: fatal: fsync error on ‘./objects/incoming-a03832/pack/tmp_idx_uBre28’: Bad file descriptor

This is happening randomly on any repository.
We are using Gitea 1.21.11
Any idea about this issue?