The jaw-dropping moment emanating from Arrowhead Stadium on Sunday evening was not that the Kansas City Chiefs lost. Heck, the reigning Super Bowl champions have dropped three of four since their Week 10 bye. They’ve also now fallen three times in a row to the Buffalo Bills … well, in the regular season anyway.

Nah, the stunner wasn’t another L in a title defense that’s suddenly hydroplaning. It was the sight of quarterback Patrick Mahomes completely losing his mind.

Talk about totally uncharacteristic.

The two-time league MVP and two-time Super Bowl MVP may be on the trail for Tom Brady’s GOAT status – futile a task as that likely is – yet he definitely hasn’t mastered TB12’s ability to go from zero to indignation. Typically when things don’t go Mahomes’ way, rarely as that’s happened in his six-year stint as a starter, he usually defaults to some kind of silent grimace, maybe even a brief protest with a referee.

But he went maniacal Sunday, screaming at officials from the K.C. sideline whilst being restrained by his offensive linemen – once the 20-17 outcome was decided – after an offsides call on wideout Kadarius Toney negated an apparent go-ahead 49-yard touchdown with 72 seconds to go, Mahomes firing up the seam to hit tight end Travis Kelce, who brilliantly hit Toney on a lateral covering the final 24 yards of the play.

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“It’s tough to swallow,” Mahomes said afterward, while also lamenting the erasure of a stunning highlight from Kelce.

“To have a flag change the outcome of the game – I’ve never had offensive offside called. If it does, they warn you. There wasn’t a warning the entire game. Then you make a call like that in the final minute?”

Chiefs coach Andy Reid shared Mahomes’ dismay and doubled down on the notion a warning from referee Carl Cheffers’ crew was warranted.

“I mean, I didn’t have a protractor out there, but that’s a bit embarrassing. I’ve been in the league a long time and I haven’t had one like that,” Reid said … even if far less stridently in his objections than his quarterback – maybe not a surprise for a seasoned boss who tends to back up his players.

Cheffers also came to the defense of his crew.

"Yes, ultimately, if they looked for alignment advice, certainly we are going to give it to them," he said in a postgame pool report. "But ultimately, they are responsible for wherever they line up. And, certainly, no warning is required, especially if they are lined up so far offsides where they're actually blocking our view of the ball. So, we would give them some sort of a warning if it was anywhere close, but this particular one is beyond a warning."

To be clear, Toney quite obviously goofed. He was practically in Buffalo’s secondary. And he didn’t check sufficiently with the line judge regarding his alignment, something receivers generally do before a play initiates.

Yet in his defense – and Mahomes’ and Reid’s – this isn’t typically a penalty that’s enforced. It’s also quite hard to come to the conclusion Toney’s break from the neutral zone had any appreciable impact in scoring the would-be touchdown, though – as a pre-snap infraction – Cheffers’ team couldn’t have known what was coming, either.

Still, consider what three-time Super Bowl referee and current NBC NFL rules analyst Terry McAulay had to say following the game.

"This is clearly a foul. (Toney) can't be past the back of the ball. His whole body is in the neutral zone,” he said.

“And I would add, in past years, this has never been called – this would be technical, this would be a warning. This year, it's been called 11 times as opposed to twice last year, only once in 2021. So this is being consistently called. He needs to be onside."

Even Bills quarterback Josh Allen, who’s lost playoff heartbreakers in this building, seemed to co-sign Mahomes’ beef.

“I originally thought it was on us,” Allen said. “It’s not a flag they usually call.”

Said another way, it’s a recent point of emphasis the Chiefs may not have sufficiently encountered or added to their offensive protocols. It also occurred a week after receiver Marquez Valdes-Scantling was mugged deep in Packers territory, with the Chiefs driving to potentially tie the game, in the final minute of Kansas City’s loss at Green Bay. No flag for MVS.

Mahomes effectively bit his tongue on that one, but it’s also fairly understandable that his stack blew Sunday as his squad fell two games back in the overall AFC standings – behind the Baltimore Ravens and, potentially, the Miami Dolphins after Monday night – and faces the prospect of going on the road for a playoff game for the first time since he became QB1 in 2018. It’s also worth noting that the hue and cry against officiating seems to be building, whether it’s Mahomes, or Browns defensive end Myles Garrett, or Steelers pass rusher T.J. Watt, or Colts owner Jim Irsay, or ESPN analyst Dan Orlovsky, or Pro Football Talk’s suggestion that Dean Blandino be rehired to revamp the officiating department, or social media’s (always reasonable) complaints on the matter.Yet this is also the obligatory time to point out that officiating a game played at the NFL's speed is insanely difficult … even with the occasional help of replay … and even if Toney’s flag was thrown as he set sail for unrealized glory. And, like Brady before him, it also sure seems like Mahomes gets more than his share of calls that his peers wouldn’t.

Remember that unnecessary roughness penalty at Lambeau Field, when Mahomes took a hit on a scramble – when he was still inbounds? Or, heck, let’s go back to the fairly minor holding flag Philadelphia Eagles cornerback James Bradberry incurred in the final two minutes of Super Bowl 57 – a penalty called to the legacy-building benefit of Mahomes and the Chiefs by essentially leaving them nothing else to do but park the ball in the spot Harrison Butker wanted before he lofted the game-winning 27-yard field goal.

Mahomes should probably take notes from the playbook of Bradberry, who didn’t cry foul after his foul. You can’t win ‘em all, Pat … even if you should be winning more against teams like the Broncos, Packers and Bills.

"Loss for words, it's just tough,” said Mahomes. “Because, regardless if we win or lose, just for it to end with another game, we're talking about the refs. It's not what we want for the NFL and for football."

But it’s probably what we’re going to get – whether Mahomes or (fill-in-the-blank superstar) is celebrating or seething.

Follow USA TODAY Sports' Nate Davis on X, formerly Twitter @ByNateDavis.