Thats the issue with a game thats 22 years old made of code on top of code on top of expansions on top of other code. You make a change to one small unrelated thing and suddenly all the NPCs in PoK spawn inside out or PoFire fails to exist or a dozen other knock on things that you couldnt possibly test because its not till you have an entire player base, that regularly checks all the obscure corners of the game on varied tasks, to explore and uncover the problems, that you even know they have happened.