In recent weeks, I have observed several times that in some cases the thumbnail generation takes quite a long time, up to several hours. For example: https://musicbrainz.org/edit/60232852 This was created at 16:44 UTC. Now we have 21:27 UTC and the thumbnails are still not generated.

Sometimes I helped myself in such cases by making the same upload a second time. As a result, the thumbnails of the first upload suddenly appeared. (Therefore, I could cancel the second upload.) A curious behavior in my view.

Is the problem known?