When you switch from minecraft 1.10 to 1.10.2 there's a chance chunks to corrupt. Umm by the way I saw that from a video and it's not in english... Umm ... Here's the video: https://youtu.be/z4cHA0WCm2A?t=13m2s and actually from a sooner part of the video you can see the client chunks are ok but from switching the version from 1.10 to 1.10.2 some chunks are corrupted. Sorry for that I can't show you a screenshot