I'm on NeoForge 21.0.78, but the issue started before that. Everything works fine in survival but trying to open the inventory in creative mode causes the game to crash.

Exit Code: -1 message: The game crashed whilst unexpected error Error: net.neoforged.fml.ModLoadingException: Loading errors encountered:

Crash Report: https://bytebin.lucko.me/ULsHK3DSvJ

I also have this issue. Neoforge had a breaking change that effect Architectury. I do not know if that is related though.
SpawnPlacementRegisterEvent renamed to RegisterSpawnPlacementsEvent

BuildCreativeModeTabContentsEvent was also messed with here: neoforged/NeoForge@2a8d908

Crash Report: https://mclo.gs/0vCZG0Q

See #539

Ahh. You are awesome. Thank you.