I know this is an old thread, but I have an iPad Air 2 on the latest iOS 10.1.1 and am experiencing this rotation bug. The iPad will not rotate, it is stuck in portrait. I have toggled the rotation lock several times but it makes no difference. Reduced motion, unlocking by Touch ID or the lock button, it doesn't matter.
The problem is that the accelerometer is essentially dead until I reboot the iPad. Apps that can read the accelerometer data show literally nothing while this bug is occurring, its as if it's been turned off. All other sensors are showing live data.
Again, if I reboot the iPad, the issue fixes itself and then comes back later at random. Very frustrating indeed. Is anyone here still using an iPad Air 2 and having this issue?
EDIT:
As if by magic, I locked the iPad and let it sit for a minute, then unlocked with the lock button (don't known if that matters) and now rotation is working and the accelerometer is showing live data without a reboot. I don't understand this bug.