You don't let the defensive player dictate that action. Lonnie knows his cover. Simply take Load Management, and wave Bryn off.I don't have time to dissect the defensive clips, but I will later. But if you look at the play with Leonard, watch Forbes. Lonnie is moving over to pick up Autist, and Forbes throws his right arm out to signal that he's got the sideline, and Lonnie moves back toward the middle of the floor. Forbes' job at that point was to do just that - cut off the sideline and force Autist back toward the middle. Instead, Bryn takes up inside position and sags, and the play goes to from there.
It's bad D by Lonnie, but the root cause is the worst defender in the league. And if you back a few seconds and look closely, it's pretty obvious that Kawhi came down the floor looking for Forbes, the victim of choice for offensive players everywhere.
While you're at it, look at the other clip around the 10 second mark. Exactly what the is Bryn doing putting his right arm out onto Lonnie's right hip? Then keep watching Forbes. If anything, he gets in the way of Lonnie staying in front of Harden. And finally, that "unfortunate" whistle was on Bryn for reaching and grabbing Harden's arm in a futile gesture.
If anyone needs to be benched, and if benching can really make a player improve, Bryn Forbes needs to have a wood-grain ass.