Extreme Entity Spawning, Over 30K

Upon playing on a friends realm, i noticed the entity count exploding like crazy every second, getting to around 30,000 entities under 30 minutes.

 

This appears to happen in only certain chunks around the world.

 

World Download: https://mega.nz/#!kUsDjQLA!S0EXNaDS5cZPgRdjBkC4G80ZaBxtUsAJzcsmfGI8lmo