This seems to be a different crash than the potential Supplementaries/Jade related crashes mentioned in #317, so I'm putting it in a new issue.

Going within render distance of a Treasure2 box while Supplementaries is installed causes this crash. It doesn't matter if it's generated by the world or placed from creative mode, and it does not happen if GottschCore/Treasure2 are installed without Supplementaries/Selene.

crash log
latest.log

Forge 40.2.0
GottschCore 2.1.0
Treasure2 3.0.0

Selene 1.18.2-1.17.9
Supplementaries 1.18.2-1.5.18

Jade issue has been fixed in v3.2.1. (and that appears to be the same issue as you're reporting by the log output).

There is mod incompatibility with Supplementaries 1.19.2. Could be the same for 1.18.2 (mixins i tell you :( )