Chunks Glitch

"What exactly happened was that i opened an old world, and then i started to load the chunks, and then about 2 rows of chunks glitched from 2 rows of the same building and then changed again rapidly"

*What actually happened was the buildings withen about a 5 chunks radius copied and paste rapidly through 2 row of chunks"

Steps to Reproduce:
1. Open an old world (1.2.5 World)
2. Load Chunks
3. Bug happened