The issue I mentioned above was fixed.
This seems to be related to Simplified category setup. It works fine when I enable that
But breaks if that is disabled
There are some places where the experiment affects sites that don’t use it. For example, the images tab was also renamed to Appearance for both interfaces, but only contains all appearance settings in the new interface. In the old one, Images fits better. But since the text was replaced, there is only one version for both interfaces