Head coach Mike Smith found out about a little-known rule the hard way during the second half Sunday.

After Jason Snelling had fumbled and the ball appeared to have been saved from going out of bounds, thus allowing the Cardinals to recover, the Falcons head coach threw the red challenge flag after seeing the replay on the jumbotron.

Problem is, all turnovers are automatically reviewed and there’s a rule for coaches who jump the gun on those particular plays. After a bit of conferring, the refs came to the conclusion that the Falcons would be charged with a 15-yard unsportsmanlike conduct penalty because the flag was thrown on an automatically reviewed play and that, as a consequence, there would be no replay, giving the Cardinals the ball back.