Taupau was penalised at the time for the incident, which saw him chase through a kick and, with Rapana at ground level to collect the ball, accidentally making contact with the knee.
In assessing the incident, referee Grant Atkins revealed it had been assess as careless.
"We have had a look at it. Marty's hands are well above [his head] and his knee's get him. It's going to be on report, and it's going to be a penalty," Atkins told Broncos' captain Adam Reynolds on-field at the time.
"Are you serious?" Reynolds replied.
"Yes. There is a careless nature about it," Atkins concluded.
The penalty, which came with just minutes of the game remaining, allowed the Raiders to get out of their own end with a six-point lead.
Rapana, who had been hit in the collision, was taken out of the game with a concussion and will miss next week's clash for the Raiders against the St George Illawarra Dragons as a result.
Despite the gruesome aftermath, which saw Rapana bleed excessively, coach Ricky Stuart said it was an accident, while also revealing Taupau had visited the Raiders' dressing room post game.
"He will be out next week, but it was an accident," Stuart said.
"I feel sorry for Marty Tauapau but it was an accident, he didn't mean to do that. He [Taupau] came in [to the dressing room] looking for Jordy earlier and spoke to his parents which was really nice of him.
"It was an unfortunate collision and accidents happen in these games.
"I hope he isn't suspended. At the moment, we are clamping down a lot on the high shots again, but what's sneaking back into the game is the number of players who are lying down, and I don't blame them either, because that's what's allowed."
Coach Kevin Walters also suggested he couldn't see how the incident was a penalty, with no malice or intent displayed by Taupau before his knee collected Rapana.
"It's the interpretation of the referees. He has obviously been injured pretty badly, but I just don't see any intent from Marty for that to be a penalty," Walters said during his press conference.
"I didn't think that decision or any other had a major impact on the result of the game."
While there was no issue from either coach with Rapana's actions, Stuart said that players laying down for a penalty is creeping back into the game.
Suspensions and charges from the match review committee are on the rise this year, and Stuart said that the amount of players lying down is impacting the game, allowing teams to gain piggyback penalties out of their own end more often.
"You have a look at so many incidents on high shots where it comes up off the shoulder and clips the head, it doesn't hurt the player, but it's a penalty. If you get the penalty, it releases so much pressure especially coming out of your end, so I understand why players want to lay down and let whoever is in the box have a look at the screen," Stuart said.
"I don't want to create a headline over it, but it's creeping back in again. I agree with the NRL trying to look after players, I really do, but it's a fast sport with high intensity, and so much collision that you are going to get a lot of accidents like that, and that's what we are seeing.
"You can't minimise the incidents. I don't think there is a lot of intent there. Hudson got Riki, but it's not intent. That's just the speed of the game, the reaction, the high intensity, the duress and fatigue they are under. That happens. It's not intentional, it's an accident.
"I don't know [how to stop players from lying down], but it's creeping back in."
Rapana's incident with Taupau cut short what had been an excellent return from suspension for the New Zealand international representative winger.
He crossed for two tries in the performance, running for 119 metres from 12 carries.
Captain Jarrod Croker, who also returned for his first game of the season, said it was typical of what Rapana has brought to the green machine over a long period of time.
"I said it after the game, I thought Rapa was one of our best," Croker said.
"Every game I've played with Rapa, he has given 110 per cent for the jersey, but that's the sort of player he is. He could not do a whole pre-season and you just give him a footy jersey and a ball and he will go for you."