iPad Air Randomly Locks Orientation When Orientation Lock is Off

Okay well. I have an IPad air 32gb Wifi only. At random times my iPad will lock is orientation. (I know that if you lock the orientation, the orientation will be locked. Duh.) but at random times the orientation will just lock up. And the only solution that I have found to fix this problem is to restart my iPad.

Does this happen to you? Is this a known bug? Is there something I can do to stop it? How do you fix it?