1.12.2 Forge
DT 1.12.2-0.9.5

Was just chopping down a Dynamic Oak Tree from the base. Entire MC server crashed.

Pastebin of Crashlog: https://pastebin.com/NbgBwkBY

Is this reproduceable?

Is this reproduceable?

I stopped this server and deleted it in early January. (2-3 Mos after that post)

I don't believe I ran into that crash again, but I only played that server for 2-3 weeks, a few hrs a day.

The crash log was pretty explicit, but I don't plan to set up another MC server any time soon, so I can't validate soon.

Yeah. It's explicit. It refers to Minecraft pathfinding which indicates that likely some sort of modded animal entity(or it's supporting functionality) isn't playing nice with an ArrayList in PathWorldListener(namely "navigations") . The only way a crash like that can happen in the notifyBlockUpdate call is if it's modified from another thread. From what I can tell my mod just happened to be in the way when this happened and thus became part of the backtrace.