Everything was going as it usually does for Kyle Bochniak backstage at UFC 220. His hands were wrapped and approved by the commission. He went over the gameplan with his coach. The referee for his fight with Brandon Davis came over and laid out the in-cage rules.

Less than an hour later, Bochniak was warming up and “getting in the zone,” as he put it, for the important fight. Just as he was about to walk out, another referee came to him and said there had been a change.

The first ref had told him the new Unified Rules of MMA would be in place for the fight; the second ref said to forget that — the commission had made a change and now it was actually the old rules.

“The ref comes in and says the athletic commission has changed it back to the old rules,” Bochniak said. “And I’m like, ‘Whoa whoa whoa, what’s the old rules again?’”

Multiple sources told MMA Fighting that early prelim fights at UFC 220 last Saturday in Boston were officiated using the new Unified Rules of MMA, while the later prelims — starting with Bochniak vs. Davis — and the main card were all officiated under the old rules.

A miscommunication between the UFC, the Massachusetts State Athletic Commission (MSAC) and the referees working the card led to the rules being switched from new to old in the middle of the event, sources said.

The biggest difference in the rulesets is a significant one: The definition of a grounded opponent. The old rules state that anything other than the soles of the feet touching the mat makes for a grounded fighter, thereby making kicks and knees to the head illegal in that position. The new rules change that language to say that a fighter cannot put just a single hand or finger down to be grounded — both palms or both fists must be on the mat to make kicks or knees to the head illegal.

“I was gonna throw a kick [during the fight], but I held it,” Bochniak said. … “I pulled back, because it looked like he was in transition of getting back up and I didn’t want a foul. Just because these rules, you don’t know anymore. I couldn’t remember what rules were in.”

Sources said a commission official mistakenly informed UFC vice president of regulatory affairs Marc Ratner in an e-mail prior to the event that Massachusetts had not adopted the changes to the Unified Rules of MMA approved by the Association of Boxing Commissions and Combative Sports (ABC) in 2016. Those changes have not been adopted in every jurisdiction, which has been an ongoing headache for promotions, fighters and referees.

However, Massachusetts has been using the new rules since January 2017 after discussions at meetings in October and November 2016, multiple sources said. So the referees went into UFC 220 under the impression that the new rules would be in effect and that’s what they informed early fighters during the standard rules meetings.

There is a blanket provision in the Massachusetts commission regulations that says if there is a question about what constitutes a foul during a fight, then the commission defers to the Unified Rules of MMA set by the ABC.

When referees backstage heard UFC color commentator Joe Rogan say during the fight between Dustin Ortiz and Alexandre Pantoja that Massachusetts had not adopted the new rules, they were confused and sought out Ratner, per sources. Ratner explained that someone from the commission told him in a statement via e-mail that the old rules were being used, sources said.

After a heated discussion, it was decided that since the commission informed the UFC that the old rules would be in effect, and that was already presented that way on the broadcast, then the old rules would be used for the rest of the event, sources said.

David Fish, the manager for UFC competitors Shane Burgos and Julio Arce, said the referee for Arce’s fight with Dan Ige, Kevin MacDonald, told Arce that the new rules would be utilized. Later on, referee Dan Miragliotta told Burgos that for his fight with Calvin Kattar it would be “changed” to the old rules.

“He seemed frustrated for the athletes and fellow refs,” Fish said of Miragliotta.

Tyson Chartier, who coaches and manages Rob Font and Kattar, said Font was originally told by referee Herb Dean that his fight with Thomas Almeida would be administered under the new rules. About 15 minutes later, MacDonald told Chartier and Font that things had changed and the old rules would be used for the fight.

“I don’t think it stressed Rob out or anything,” Chartier said. “He was like, ‘OK, whatever.’ It was definitely interesting. I don’t know what was going on, but it was definitely interesting they couldn’t figure out what rules they were using.”

Gian Villante, who fought Francimar Barroso on the main card, said he was told the old rules would be used. Alexandre Pantoja, who fought Dustin Ortiz on the FS1 prelims, said his referee told him it was the new rules. Ortiz landed a knee to his head during the course of the fight and Pantoja said he felt it was illegal based on his understanding of the rules.

“It’s complicated to fight in the U.S. with an American referee and three American judges,” the Brazilian said.

When asked for comment, the UFC referred all inquiries to the Massachusetts commission.

In a statement, a spokesperson for the Massachusetts Division of Professional Licensure said: “There was an internal miscommunication about the rules, however, all of the fighters and officials understood which rules applied for their matches.”

Bochniak said the sudden change in rules mid-event didn’t necessarily affect anything about his fight, which he won via unanimous decision. All the competitors and referees at UFC 220 seemed to know what rules were being used for their respective contests before walking out to the Octagon — even if those rules were different in other bouts.

“It wasn’t that bad, it just threw you a curveball a little bit,” Bochniak said. … “It wasn’t too much. It didn’t throw me off or anything. I just never saw that before.”

Additional reporting by Guilherme Cruz and Ariel Helwani was used in this report.