Navigation bar randomly appearing and staying up

My tablet doesn't have hardware navigation buttons like for Home, Back and Task List, so Android Kit Kat (4.4.4) shows them on screen. You normally get them to show up by swiping down from the top of the screen. Since the update the navigation bar will randomly pop up without me swiping down from the top of the screen. It has mostly happened in the town but happened on the farm once too.

When it comes up it stays up so the first way I noticed it was because I couldn't click on the "friends" button.

I noticed that it is only the bottom bar that comes up, which I've never seen before on my tablet. Normally when you swipe down a transparent navigation bar comes up at the bottom and a transparent notification bar comes up at the top. When this bug is happening it only comes up at the bottom and just stays there.