Seems I previously posted this in the wrong thread.
It's still an ongoing issue in iOS 10.x. My mini 4 screen rotation sticks, and instead of restarting, the quickest way that I've found to correct it is to open the camera. After the camera is opened you can see the camera controls go to the appropriate orientation, and rotation works fine after that...until is randomly sticks again. I've had beta 10.2 on it as well, and the rotation still sticks from time to time. I reported the sticking issues in betas for 10.1 and .2 to Apple. Also, my wife has had the same occurrences on her mini 4. Who knows when/if they'll identify and resolve the issue?!