pastafari

@root

That’s what might be causing some new problems (with lightbox etc.) since we had to use this workaround and that’s why I’m desperately looking for a fix for the initial problem.

@pozhonks

I already wrote above that that’s exactly the ugly workaround we are currently using. I hardly think that it is a very good “solution” to the problem though. I would be really much more interested in a real fix to the problem or at least a reason why this might be happening.

@varkyl
I’m not sure if that is what causes the behavior in my case. There are two completely separate wordpress installations with different databases, themes, content etc. on the server, both in different folders (one in /wordpress the other in /subfolder/wordpress). Only the older blog in /wordpress shows this odd behavior and only after moving from a shared server to a dedicated one (both with almost the same setup however).

This problem also occurred before the upgrade to 2.0.6, so if this is indeed a bug in WordPress it was already present in 2.0.5. WordPress 2.0.5 however seemed to work fine on the old server.
I just don’t understand how this could happen and why it happens seemingly randomly and after some hours only. What triggers the switch back to the default theme?
I just noticed that at least with the current setup (default theme replaced by our modified k2-theme) the Lightbox-Plugin doesn’t work anymore either, but I’m not sure if or how this might be related.
Everything else seems to work normally.