[GAMEPLAY] Protobelt active failed to cancel recall

I was playing as lissandra. The enemy Lee Sin had about 2 seconds left on his recall; I dashed forward with protobelt, which hit him, and then q'd and auto'd him expecting to see a kill momentarily. My auto proc'd thunderlord, proving that he had already been hit by my protobelt bolt, and yet he did not have his back cancelled, as the q and auto damage went through after the recall could be stopped. This seems like a rather important bug as protobelt damage certainly should cancel a recall.

http://matchhistory.na.leagueoflegends.com/en/#match-details/NA1/2327410359/49727128?tab=overview Link to the game, this happened sometime around 15 - 20 minutes near the topside red buff.