Chunk loading errors in world made in previous versions

Im on a barns and noble nook hd tablet, When loading a previously saved world before this update I've noticed that there happens to be a chunk in every world I reopen that crashes the game when you either look at it or when you step into it backwards or sideways. I always happens in the same chunk every time in dozens of worlds I have. It does not affect newly generated world. (It actually just happened to me in a newly generated flat world the seed is 763018729 cheats on, creative, and normal difficulty, and I'm sure it does not later but I named it beacon. At spawn I built a beacon and close to that i spawned a wither and killed it. And I went for a run around my beacon and when I looked where the wither died it crashed. I have not spawned the wither in any of my other worlds this crash happens. Also in the enclosed pictures is the beacons I built and in the first picture in the top left is a hole where the wither destroyed the ground. The second is the crash after I looked left