Little update. I don`t know exactly what happend, but now pressing J when I play a table brings me reliable back to the PinballX menu. The only thing that I noticed is the following. Pretty often If I start the next table, the buttons like start and coin do not work. I have to remove my VR glasses, go to my mouse and leftclick on the active window for the game. Then everything works again in VR, too.
log.txt
PinballX.ini