UFC 220 used two different sets of rules
Kyle Bochniak: “Just because these rules, you don’t know anymore. I couldn’t remember what rules were in.”

The Unified Rules of mixed martial arts are not unified at present. At the 2016 Association of Boxing Commissions and Combative Sports convention, refinements to the rules were adopted. These included a new definition of a downed fighter, means for referees to more ably stop eye pokes, a lifting of the prohibition on heel kicks to the kidneys, new judging criteria, and more. More complete details can be found here.
The new rules passed with near unanimity. Rhonda Utley-Herring, representing the New Jersey Athletic Commission, voted no, and offered a detailed explanation as to why. The membership did not find it compelling. Mississippi voted not present. And there was an abstention from Tennessee, which no longer has a functioning athletic commission. The rules are set to take effect on January 1, and while some commissions instituted them quicker, others still have not.
This has lead to a situation where fighters, judges, and referees have to use different rules sets from week to week. It’s absurd, and it got worse still at UFC 220 in Boston, when two different rules sets were used in the same event.
Marc Raimondi, with help from Guilherme Cruz and Ariel Helwani, reports for MMA Fighting that the first five fights were done under the Unified Rules, and the final fight in the late prelims and the main card were done under the old rules. The change came right before Kyle Bochniak fought and defeated Brandon Davis.
The ref comes in and says the athletic commission has changed it back to the old rules, said Bochniak. And I’m like, ‘Whoa whoa whoa, what’s the old rules again?’
I was gonna throw a kick, but I held it. 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.
The fiasco was due to a Massachusetts State Athletic Commission (MSAC) official mistakenly telling UFC vice president of regulatory affairs Marc Ratner that the old rules were in effect. However, Massachusetts officials held meetings in October and November of 2016, and adopted the new rules starting on January 1. Further, Massachusetts regulations explicitly state that if there is a question about the definition of a foul, then the commission defers to the Unified Rules of MMA set by the ABC. The local referees informed the fighters and all was good and normal.
Then, during the fourth fight, referees backstage heard commentator Joe Rogan say that the new Unified Rules were NOT in effect. The confused refs reached out to Ratner for clarification. Eventually, it was decided that as the commission had told the UFC that the old rules were in effect, and as that had been broadcast worldwide, the old rules would be in effect for the remainder of the event. Fighters were then informed of the change backwards, and the show went on, confusedly.
The ABC group that crafted the changes is a dream team, that included fighters Randy Couture, Jeremy Horn, and Matt Hughes, referees ‘Big’ John McCarthy, Robert Hinds and Kevin McDonald, and regulators Sean Wheelock, Matt Woodruff, and Brian Dunn, and Dr. David Watson. A number of members of the group have deep expertise in multiple areas. McDonald and Dunn, for example, are former fighters. Wheelock was at UFC 1, as was of course McCarthy.
The sport is undeservedly thrust into clown shoes at moments like this. The central effort at the 2018 ABC convention must be unifying the Unified Rules.

