This is one messed up executed play.
First, the crosser wipes out Knox's defender allowing Knox to be wide open.
Second, Josh has a tendency to lock onto the receiver he's going to throw to. Here he locks onto # 5 (Palmer) waiting for him to clear the deep safety. That's why he's cocked before anyone is in his face but doesn't deliver until he's pressured resulting in an underthrown ball off his backfoot.
Third, Palmer hesitates at the end of his route seemingly settling into a gap in the zone instead of continuing across the field. This results in him not being where Josh thinks he'll be when he releases the ball.
This play is illustrative of what I see from this year's Bills team -- failure to execute. That's not the only problem (injuries, etc.) but it's a major one.
Thoughts?