TrinityCore/TrinityCore — pull request #12216 by Trisjdc (2014-06-05 10:18:38+00:00)
Title: Core/Players: Improve quest item adding/removal checks, solves cases where quest item removal (under specific conditions) incorrectly incompletes quests

https://github.com/TrinityCore/TrinityCore/issues/11947, and probably more