What Happened:

I was loading into a newly generated world and as soon as I started loading in, I got a crash. Based on what I can see, it looks like it was a failure to invoke a method, due to a field being null? No field names, so I can't say much more than that.

Crash Report (link because too big to be a collapsible):

https://hastebin.com/share/mawasusovi.yaml