I don' think it was the yellow sleeves. I think
so
- the referee was unsighted and under the impression that the ball was being carried by an attacker -- but wasn't sure whether the ball was grounded over the line or not.
- he asks if it was grounded.
- the TMO can see that it was a defender with the ball, but it doesn't occur to him that the ref thought otherwise, the TMO thinks the ref is worried about whether the ball touched the ground to give away a 5m scrum
- the ball DID touch the ground, so it was a 5m scrum, TMO confirms simply, that the ball was grounded. He doesn' mention by whom, as to him it was obvious
- the ref - for whom this whole discussion has been a try / no try conversation ... hears th eball was grounded so naturally awards the try.
Without hearing all the conversation we can't tell whose fault it is. Someone wasn't communicating (or someone wasn't listening)