Default Data Pack is not loading/new updates not working

My DEFAULT data pack is broken and won't load some update data. I have no other data packs on, and haven't changed anything. I obviously can't remove it or try and reinstall it, as it's part of the game. Old/new worlds I generate have this issue, with one example being that sniffers are completely invisible for me unless I create a copy of a world, which somehow fixes ONLY THAT ONE thing.