Some chunks got inverted after a reboot of the server

Issues :
[15:37:41] [Chunk I/O Executor Thread-1/ERROR]: Chunk file at 61,-1 is in the wrong location; relocating. (Expected 61, -1, got 47, -5)
[15:37:41] [Chunk I/O Executor Thread-1/ERROR]: Chunk file at 52,-1 is in the wrong location; relocating. (Expected 52, -1, got 53, -2)
A Chunk
https://cdn.discordapp.com/attachments/264436904349532160/328894515039698944/2017-06-26_15.45.57.png

Not enough information provided.