Hard to see the miscommunication, that throw never should have been made. No route adjustment built into that play call is stopping the DB from undercutting the route.
The WR probably didn’t expect the ball because he had the DB sitting right on top of him, he’s basically running a clear out route at that point.
How do you know what the route adjustment was built into the play call? Your saying the offensive coordinator called a play where the wide receiver had no responsibility on the route and the QB knew that and threw it anyway?