Vanilla server, no plugins/mods.
Chunks that have been loaded and built in are appearing in newly loaded areas. The 'original' chunks are untouched. Not much more I know right now.
Haven't posted a bug report before, sorry that this is very vague.
MC-79953
Chunk copying
Resolved
Duplicate
0
Joseph Cryer
(Unassigned)
Unconfirmed
Minecraft 1.8.1, Minecraft 1.8.3, Minecraft 1.8.4
Retrieved
This is MC-2548