Yeah, the ref gave the card not for the particular act but as a result of the number of penalties we were conceding in defense, particularly against their lineout maul.
There's a pretty finicky argument that you can make against the decision. The laws in question are below:
Repeated infringements
8. A team must not repeatedly commit the same offence.
- It was the first time that we conceded a penalty for that infringement.
9. A player must not repeatedly infringe the laws.
- Murphy had not conceded a penalty since arriving on to the pitch.
10. When different players of the same team repeatedly commit the same offence, the referee gives a general caution to the team and if they then repeat the offence, the referee temporarily suspends the guilty player(s).
- The offence that we had been repeatedly penalised for was collapsing the maul Law 11a: "Players must not:Intentionally collapse a maul or jump on top of it", not interfering with the player in the air – the latter comes under Law 17 Dangerous Play: "A player must not tackle, charge, pull, push or grasp an opponent whose feet are off the ground." So while we had been cautioned for repeatedly pulling down the maul, we hadn't been cautioned – or even penalised – for playing a player in the air.
https://www.world.rugby/the-game/laws/law/9
To be honest though, I have no complaints about us getting yellow cards in that game. We couldn't deal with their maul and if the circumstances had been switched, I would have expected yellow cards on the other side.