Server .jar crashes with no discernable cause. Lots of latency with environment interaction for players on the server.

What I expected to happen was...:
Running a previous (non snapshot) version of the server .jar there were no issues with the same players. I expected similar performance.

What actually happened was...:
Lots of environmental interaction latency and server crashes.

Steps to Reproduce:
1. Play the 14w30c snapshot on my particular server
2. Experience server crash