I don't have a K3-II for testing. I wouldn't object to having one, of course, but my wife thinks the money would be better spent elsewhere
I think someone else was having some issues with the K3-II as well. I can't recall where that conversation ended up, but I think the issue was related to this thread:
. So perhaps try astrotracer mode instead of bulb, and make sure that bulb mode is in press-hold mode? Oh, and just in case, make sure you're in MSC/MFT, because I suspect PTP does not support bulb on any camera.