He slide right into the bag.
Hated the call live and was surprised to see it called. Then on review you see the runner slide to the inside of the base (his right knee comes over the top of the 3B side of the bag w both his whole left leg and right foot all inside the bag.) The fielder catches the ball inside the bag, steps further in during the attempted transfer and gets contacted on his left foot by the runners right foot. So by the letter of the rule, the runner looked to make forcible contact outside the base width. So I don’t know how they overturned it beyond they didn’t want the deciding game to end on an obstruction call.
live I still thought the play should have been allowed. So it worked out. I just didn’t like the call being overturned on replay.