This isn't to defent the performance of Dawkins but on this play he has no chance of stopping his man when Josh moves up in the pocket.
Dawkins is on his man all the way back but when Josh moves up, Dawkins doesn't know it and that movement gives Dawkins' man inside leverage to Josh. There's nothing Dawkins can do at that point so he stops.
Again, I'm not defending Dawkins' overall performance, just that this play does not illustrate Dawkins giving up on the block.
On an unrelated note, for someone at the game, were many of the sacks coverage sacks?