[GAMEPLAY] Thresh going trough the dragon pit wall like Kayn

Thresh was on the blue side of the dragon pit, used his q on me, while I was on the redside of the pit. He reactivated q, and entered the pit with it. I used my W as Janna on him, and at that moment he started to go trough the pit wall, back to the blue side of the map. I do not know if it's a replicable bug, I just saw it once, and didn't try to do it again.