i have nfl+, rewatched the miami game in the coaches all-22 mode
not once did the primary defender on diggs make a tackle or get contact on the runner.
in fact, on a couple of plays the run went to diggs side, the db was too close to the line of scrimmage and the runner went easily by.
forget about relaying the info to the other players that diggs is not going downfield....anyone looking over that way takes himself out of the play in a second.
this is not hurting the bills in any way