Description of the issue:

Using IE fluid pipes connected to Advanced Generators (0.9.20.12) heat exchanger(outputting steam). Sometimes the pipe doesn't visually "connect". Occasionally when exiting the ui of the machine or looking at the pipe connection the client will crash.

Crashlogs:

https://pastebin.com/rF2uWBfk
https://pastebin.com/QZtmSjLj
https://pastebin.com/MmRPZFDr

Additional pipe crash
Description: Tesselating block model
https://pastebin.com/7T8Y197r

Versions & Modlist

Forge: 14.23.2.2651
IE: 0.12-80
Pack: Sevtech Ages 3.06 (unmodified)

I can't find source code for advanced generators on 1.12 right now, but I'm quite sure the first crash is on their side.
The second crash looks interesting, do you remember when/how it happened?

I believe it is when I tried to hook a pipe to an astral sorcery lightwell.