This was my crew's pregame play discussion this week. We discussed the momentum rule but talked more about mechanics. Not that they are more important than the rule but in this case, there was a universal breakdown.
The one thing on this play that I'm going to give the BJ/SJ a break on is the knee. Real time, they may not have believed (or been sure) the knee was down and continued officiating -- which was the correct thing to do. However, once the ball was thrown, the flags should have been thrown (I believe) into the end zone.
Since it was a forward pass that was incomplete, do you believe an incomplete pass signal should have been given? There is a split among us that think that. Some say no, a stop the clock suffices. Others say, yes, because if players think its a fumble, they'll go after it and heads may knock together. I'm leaning toward yes, but I'll concede the players are going after the ball anyway (here, I think it went out of bounds, but for general mechanics purposes).