Default theme broken after recent update

I recently upgraded to v2.1.0.beta4 +50 and noticed that all my customizations that my default theme lost all its child themes. In fact, it is not even the default theme any more. It is still called “default” but it is no longer enabled by default:


Strangely, none of my themes and the components are marked as “enabled by default” (i.e. none has the asterisk).

What happened and how can I fix it?

Edit: another oddity: I have the the Private Message Clarity theme component installed (but I don’t think I ever used it) and it now seemed to have a theme component that I created myself called “Hide fields on invite page” as a child. That was very weird since it makes no sense at all. So I tried to look into it and after a few clicks (just browsing, no editing) the Private Message Clarity theme component no longer had any child theme. I suspect that it’s a display issue because I had just previously added the “Hide fields on invite page” as a child to the default theme. Somehow, that led to it being displayed as the child theme of the subsequent theme component I looked at.

I have seen this on multiple forums now. I think on at least one of them, the Material Stock theme was installed and renamed to “Default” (while the old default was renamed to “Default (old)”. Could that have caused some strange stuff?

Possibly related:

Is it related to the change discussed here?: