This is the first time I really analyzed that play (I had to go pick up a pizza down the block).
The way I heard people criticizing Brock I figured it was a horrible throw and he got lucky. I see a flag, it was PI on Detroit so it wouldn't have mattered if he dropped it or even if it was an interception...also the ball probably hits Aiyuk in stride if he doesn't get bumped.
Fantastic play by Brock and it's hilarious I've heard it described as lucky and a bad throw.