I can definitely confirm this. In full screen it's fine, but when my wife plays with me on split screen, which is most of the time, it's not playable. I just avoid the onslaught playlist altogether. Well, that s&r sucks, imho. I'll try to update with a screenshot. In private match, split screen seems to work fine too. It appears that Bayview only breaks when playing in matchmaking.
P.S. I play on Xbox One.