Server Crash: Exception in server tick loop

After upgrading to Sponge 1538 the server hasn’t crashed for days. Now that I allowed players on it, it crashes 16 times a day with the same crash report. Honestly have no idea what would be causing it, any assistance would be greatly appreciated.

http://pastebin.com/rgqDmw30

This error looks to be caused by a mod spawning entities off the main thread.Did you add any new mods recently?

Negative, for about 2-3 months (with the same modlist) it’s only been 1-5 players on and we were building the world. We could be on for 24 hours and not have a single crash or lag issue. Now that our server is public, players that are spread out across the world, cause TPS to drop and then the random crash happens. Sometimes it’s once an hour, sometimes you can go for an entire night without it crashing. I’m thinking it’s Thaumcraft but if it’s such a popular mod, wouldn’t others be having this issue?

One thing I’m failing to understand is that due to the below timings report, mob spawning is causing a lot of lag. There are hardly any mobs on the server compared to previous versions of Minecraft where players can get swarmed. Not sure if that’s a Sponge thing.

https://timings.aikar.co/v2/?id=877678ed7b39414aa629fd74382f2d3c

Hmmm been getting the same as well, at random times. Can’t be sure what is causing it.