Mods routinely ship recipes without the advancement that puts them in your recipe book, so those recipes stay invisible forever. Others ship advancements written for pre-1.20.5, where the removed item/tag predicate keys leave an empty condition that matches every item, so the recipe unlocks on your next pickup, whatever it is.
Errata fixes both: it unlocks the forgotten recipes from their most distinctive ingredient, and rewrites the broken advancements into correct syntax via a generated datapack. Mods with working progression are left completely alone.
