IMO, no I don't think that this was a PT. At the very worst it was a Penalty advantage for the tackle by #19 Red.
For me, take the foul play (the high tackle) out of the equation and then you have the ball carrier already tackled by red. Assuming this tackle wasn't completed then you have a defender sprinting across from the (left) wing who could have made the tackle. This is why I don't believe that a PT was correct in this instance.
But, as the Laws state, the referee is the sole of judge of fact on the field of play and he adjudged it a PT offence. FWIW I don't recall seeing the YC issued to the Red 19.
I can't even see a PK offense. I can only imagine the ref THOUGHT he saw a high tackle.
Meanwhile even if it WAS a PK offense - a PT? their's another tackler also tackling him, with a covering defender arriving at pace from the right
13. A player must not tackle an opponent early, late or dangerously. Dangerous tackling
includes, but is not limited to, tackling or attempting to tackle an opponent above the
line of the shoulders even if the tackle starts below the line of the shoulders.