MAJOR game breaking Bug

Master Yi can kill a Tryndamere in ult. I am not sure if it's a bug to do with the new devourer item and perhaps his ult isn't properly phasing out the devourer damage, but it happened every time I fought Master Yi, no matter what point I used my ult, we even just fought to test it and sure enough, Master Yi can just straight up kill Tryndamere in ult.

Its a good thing we still won the game, because 4 fights 1 on 1 this happened, and even the Master Yi was confused. Again, this only happened against Master Yi, still unsure if it is Master Yi, or the item in general, but beware tryndamere players, there is a massive bug that can seriously determine the outcome of a game