My iPad mini keeps getting removed as a trusted device

Hello, it's almost been a month since the problem first happened. I reseted my password and my device still keeps getting removed from being a trusted device. Every time this happens, I always feel angry at the problem. I also keep getting this message saying that my Apple ID is being used on a new iPad for FaceTime and iMessage and I don't have a newer iPad. How can I fix this issue? I am running on iOS 9.3 Beta 3 and not iOS 9.2.1.