The latter issue sounds like a camera fault, mine has never locked up, and I don't think I have heard of others either.
I set my rear screen to use the lower quadrant and use relative mode to move the focus points around, and this greatly reduced the chance of the focus box moving to some other area due to my nose touching the screen. Until then, I had that happen a fair bit of the time.
You will experience the same thing with the RP and R, they all share the same tech and programming especially in this regard.







