Several versions ago I encountered an intermittent bug which took the form of random presses on the fire button, equipment buttons, etc. It made the game unplayable until I figured out that it only happens when the device is plugged in. When running on battery, no problems. The bug went away with an update and I forgot about it until a couple of days ago. For whatever reason, it's back. It's not a huge problem since I can just avoid playing while charging the battery, but I thought this might be helpful for anyone experiencing the same problem.
iPad 4 32 GB wifi, iOS 9.2, not jailbroken.