Server crashed again. Both were caused by a ticking entity (a slime), and it appears that the cause may actually be KCauldron. So, I'm going to revert to using the old method of running the forge .jar. It will be slower and there will be lag, but there will be no crashing hopefully.
EDIT: Attached crash log
EDIT 2: After making a batch file to run the server with some args to improve the performance of the server, it actually runs really well.