Arkham Horror
Why do Codex cards 3 and 5 both have a three-clue trigger that adds card 4, and does card 5 add card 4 again?
Card 5 keeps its clue trigger as a fallback, so card 4 still enters the codex if it was never added. If card 4 is already in the codex, the redundant trigger does nothing. The overlap is an acknowledged wording oversight.