crash-2023-04-04_23.44.33-fml.txt

This particular line is the causing the problem in the crash above.

When adding things to vanilla maps during modloading, you need to be careful as that can cause this specific exception to be thrown.

Simple fix is to use the enqueueWork method from FMLClientSetupEvent, and call ItemModelProps#register inside the Runnable instance passed into it.

Oh shoot, thats a silly overlook! Thank you for letting me know!