I've been running Tumbleweed for a couple of months.

It started crashing back to SDDM the first time I tried to log in. The second try would work.
Now its worse.

First time I log in, It successfully starts dolphin and konsole, but any subsequent applications fail to start. when I start them from within konsole, they complain about an invalid MIT-MAGIC-COOKIE-1 key.

The kde menu is there, but using it to log out does not work (presumbably for the same reason).

If I enter "killall kdeinit5" from within konsole, it puts me back to SDDM, and a subsequent login works properly.

I'm baffled. Any suggestions?