In case it's relevant, I play sitting down, so I know I'm not turning at all, but every time I reset view, it shifts the screen ~30 degrees to the right. I've tried facing different directions (I have a 360 degree setup with 3 sensors) to see if that would help with the issue, but the same things happen: I start automagically selecting a hotbar item, I reset the view, and it shifts my focus 30 degrees to the right.
I have also tried it with the minecraft window having focus on Windows and with having a browser window on top of it, in case there was a weird mouse interaction going on. That doesn't seem to make any difference.