When I use the supplied Camera app, take few pictures, switch to 2x camera, maybe wander to Video and back, then suddenly (not always) when I switch to 2 x camera (or zoom) the Camera app "freezes" and stays frozen. I have got to close the camera and restart it (is starts in 1x mode and works) but then the phone is "spoiled" until I restart it - e.g. any attempt to switch to 2x gets camera app frozen. When I try to switch to Video it would say (after 5 sec hangup) that it "Cannot connect to camera - Dismiss/Try again"
Also when that happens, the built-in Torch cannot be lit, after 1st attempt and failure the button in tray is greyed out and 3rd party torches say "cannot connect to camera".