In my mod pack Create on a Potato PC it seems the Mysterywood sapling is crashing our server. It seems to crash when the sapling is trying to grow. I tested in a singleplayer world and if I bonemeal it the sapling disappears, but the game does not crash. I had other players test this and they found the same behavior.

Minecraft: 1.16.5
Forge: 36.2.9
Forbidden & Arcanus 16.2.1

crash-2021-11-21_20.24.00-server.txt
Same report above in Crashy
https://crashy.net/Qul2imuf96DnaMSxlV69

Fixed in 16.2.2