When did this get in the game?
With one of the last patches/fixes
What happens if you crit fail a skill?
just because he rolled 1 and his 5 points of well earned knowledge are not taken into account
Same as with critical miss, you roll 1 means you fail, proficiency is ignored, buffs are ignored.
Yeah, that's def not a 5e rule, not sure what it adds to the game, or what the thinking behind it is.
My guess is that it came in the game because many people who don't really know the rules were complaining otherwise:
https://twitter.com/larianstudios/status/1448698868556701701