https://github.com/progwml6/ironchest/blob/1.12/src/main/java/cpw/mods/ironchest/client/ClientProxy.java#L35 registers tesrs with a null te class from both loops where the type is VANILLA. This doesn't make sense and should normally crash if FML validated the inputs properly.

Currently this bug has no effect I am aware of, it just pollutes the tesr map with null keyed entries.