What I expected to happen was...:
I would see a normal super-flat world

What actually happened was...:
When I put me render distance to 16 chunks, a nearby village was visually duplicated in a large grid over several chunks...

Steps to Reproduce:
Put render distance all the way up.
The village stayed glitched even after I left the game and came back.

NOTE: I doubt this only applies to villages, and I only saw it happen in that world.