First up, Colby's tackle was a tip tackle by the WR (World Rugby) definition. Legs were held above the rest of the body as the tackle was made. It was contributed to by the presence of another Rebel in the tackle as well, but Colby was primarily responsible for the legs being held above the body.
I also thought, at first, that AA's tackle was possibly no arms, but the replay shows he actually bound on the ball from the outset.
Can't say that I saw the suspect tackle apparently made by Sam Carter.
The biggest issue from the game imo is why wasn't Mafi cited for the hands/fingers over Sio's eyes? Put this with the failure to take action when a similar thing happened to Kane Douglas, and it is becoming clear that WR (World Rugby) edicts in some instances are having little or no effect.