Bug of Powder Keg, E of Gangplank

Powder Keg, E of Gangplank, described as " If Gangplank destroys a keg, it explodes dealing the attack's damage as physical damage (ignores 40% Armor) to enemies and slowing them by 40/50/60/70/80% for 2 seconds". Though the damage from TRINITY FORCE and ICEBORN GAUNTLET could be correctly applied when the keg is destroyed, the damage from LICH BANE could not.