Can't add to existing collection (list of collections empty)

[Sagrafin]

There SHOULDN'T be a difference.  But I've seen users experience weird issues that don't exist with the official image.  Some that I've been able to reproduce in testing.

Give the official image a try in a test container and report back if the problem still exists there.

It works with a fresh install of the official image. So the problem is either because of some specific configuration (or plugin), or it's a general problem in the unofficial image. I'll use the official image and report back if the problem should appear there as well.