Visual display issue

I have a world in Pocket Edition that has lots of buildings in it but when I went to add a roller coaster and put fence segments under it, a part of the fence section would not be visible, but still be thee, able to be destroyed. When I destroyed certain fence segments, than the rest of the missing sections would reappear. So I built around it. When the update came out, the whole area is screwed up visually. The game always closes out when I get near, or look directly at the glitch, but when I am able to it looks as if a whole section of the world has been smeared. I have photos is you want, but please try and fix this irritating issue.