The players knew they would be pinged for attempting to sack the maul the way they were, yet the questionable entries kept coming and so did the whistle.
Liam Messam spent much of the half in constant conversation with Joubert but the discourse did little to alter the outcome, with the continual infringements seeing Michael Fitzgerald and Ben Tameifuna both sin-binned. The Chiefs' frustration, though, was understandable.
"It was a hell of an arm wrestle in the first half," Rennie said. "Craig Jourbert wasn't happy wth the way we defended mauls, and punished us accordingly.
"Obviously it's something we'll have to look at but it's pretty much what we've done for the first half of the competition. We'll have a chat to him around why he ruled that way."
No8 Michael Leitch, who scored the first of the Chiefs' four tries, echoed his coach's sentiment.
"It's hard when we've been playing like that for the whole competition and, all of a sudden, we're getting pinged for something we've done the whole time," he said. "But the leadership group really took charge in that area and fixed it up."
There was no debate around that fact. The second half was a totally different story after the Chiefs had made the requisite adjustment. One, to state the obvious, was to avoid giving away penalties; the other was to shy away from kicking for touch.
Those combined measures removed the Cheetahs' maul from the game and gave the Chiefs a territorial advantage they had been lacking. The penalty count finished 16-8 and, with Aaron Cruden landing all seven attempts from the kicking tee, the hosts controlled the latter stages of the encounter.
But Rennie knows his side's discipline must be tightened. The Chiefs lead the competition in cards received and penalty goals conceded, somewhat spoiling a defence that has allowed only a try a game.
"There's no doubt - we don't want to be giving away penalties," Rennie said. "It's hard to get in games and you don't win games with [yesterday's] sort of penalty count. Obviously we'll talk to Craig but we've got to look at ourselves. You just can't give sides opportunities, especially at this level. Everyone drives pretty well, so we'll have to better."
That aim will begin with a home match against the Blues next week and, set to be boosted by the returns of Brodie Retallick and Tim Nanai-Williams, Rennie was satisfied with his team's standing before the forthcoming bye week.
"The fact that we travelled back from Africa, that we had a huge disappointment last week, to get five points [yesterday] was pleasing," he said. "It's still not where we want to be but we're moving in the right direction."