I'm unhappily joining the club!
Today my K-1 was almost stuck to M mode... I say almost because when I turn the mode dial sometimes it goes to other random modes but not those indicated on the camera dial and sometimes it even goes M mode after a few seconds... It's the first time I had a problem with a Pentax camera.
What I observed is that if I press the central button that allows you to change the mode it shows the correct mode that you have chosen! But when you ease the pressure the M mode appears again on the screen and the camera really works on M mode only...
Using the unlock setting to switch the mode dial doesn't help. There is some lost connection in there as the needed pressure shows.
Now the service in my country kind of worries me... Let's see how it goes.
I have been using my K-1 without any other issues since the beginning of May so it's 2+ months old...