View source for Unable to logout or go to account settings

As you can see from the screenshot, I'm logged in, but when I click on "Account" (upper right corner), I'm redirected to this page. Please, also notice that strange ##?lpAz## at the end of the URL.

((https://upload.adminforge.de/r/UJRZuBv_2j#cBUBeBLL4cTxXASDw6aPP8Q0hQrhEt+nC7FLVytYWi0= https://upload.adminforge.de/r/UJRZuBv_2j#cBUBeBLL4cTxXASDw6aPP8Q0hQrhEt+nC7FLVytYWi0=))

When I click on "Logout" (upper right corner again), I see this:

((https://upload.adminforge.de/r/D2E2nmnwWH#t0n773L2CJLJAHf4CHDrK2TqjCyHYUknRPSPSxmbfoY= https://upload.adminforge.de/r/D2E2nmnwWH#t0n773L2CJLJAHf4CHDrK2TqjCyHYUknRPSPSxmbfoY=))

"Delete all cookies" seems to work at all, but it doesn't help against the problem described above.

I'm using Firefox 122.0.1 and already deactivated all plugins. WackoWiki works fine in a private-mode tab or in Chromium 121.0.6167.160.

Any ideas?