The current pre-release of the client ("pioneer" in the version) is only compatible to itself. So you can only play with other testers. Please be aware!
Thanks for your comments guys, at the time where I wrote this I was pretty sure that I did not ctrl-k something, but even "pretty sure" means not 100%
I thought there is a way to see from a game report or anything beyond if my keyboard actually triggered it. Anyway, lets go on and see if it happens again ...
Happy FAFing..