When Bao is hitting golf balls into the container of water, there are 2 balls on the mat. He hits one more shot into the water then turns to walk back inside. The shot shows that there are still 2 balls on the mat.
They left the flag stick in when putting out. That's a penalty. Someone in the crew should have known that.
When Jack picks up Elliot, at 4:41 , you see a big red spot on the seat of his pants.