Due to the BrewingStandBlockEntityMixin's writeNbt hook, when saving the world chunks containing a brewing stand will load themselves, wasting a lot of CPU time and permanently looping the game.

I have a lot of mods, so this may possibly not be reproducible with just Resourceful Tools, however I believe writeNbt is not an adequate place to query for neighboring blocks. Perhaps it could be done in tick or something like that?

The brewing stand mixing has been changed to using tick() in the coming 1.21 release.