I'm no QB guru, but what I consistently see when Goff's is playing poorly is that he waits until his receiver is open before delivering the ball. In doing so his passes are arriving late, the timing is off, and the defenders have time to cover.

When he's playing well he's throwing to a location and letting his receiver makes the play. I wonder if his success vs Tampa was because the defense was in his face the whole game and he couldn't actually see his receivers (LOL!)

I can't imagine he is being coached to wait and I think it's what happens when he starts playing "in his head". We have more success when we are playing hurry-up and I think that's because it doesn't give Goff time to think, but instead play by instinct.