The UFC crowned Germaine de Randamie its first female featherweight champion in February, under the assumption de Randamie's first title defense would come against Cris "Cyborg" Justino.
Those plans have hit a serious snag, however, as de Randamie (7-3) has stated, through her management, she will not face Justino in the Octagon.
"Germaine and her team have talked, and the position is that she will not fight Cyborg because Cyborg is a proven cheater," de Randamie's manager Brian Butler wrote in a text message to ESPN.com.
"Even after so much scrutiny has been put on Cyborg, she still managed to pop for something and will always be a person of suspicion who is trying to beat the system rather than just conforming to the rules.
"For that reason, Germaine and her team don't believe that Cyborg should be allowed to compete in the UFC at all. If that is the only fight the UFC wants, then Germaine is willing to wait and see if the UFC will strip her belt before making her next move."
In 2011, Justino (17-1) tested positive for the steroid stanozolol following a fight under the Strikeforce banner, and was suspended for one year.
She tested positive for a banned substance again in 2016, but received a retroactive therapeutic-use exemption from the United States Anti-Doping Agency (USADA) and was cleared of any wrongdoing.
Justino replied to de Randamie's stance on social media.
"Some people are so afraid to lose they will find every excuse not to try," Justino wrote on Twitter. "You can't doubt yourself champs are confident."
Fighting out of the Netherlands, de Randamie won the UFC's inaugural 145-pound championship by defeating Holly Holm in a five-round decision at UFC 208. The UFC flew Justino to Brooklyn to attend the fight, and she and de Randamie even squared off backstage at the conclusion of the event.
Shortly after the win, however, de Randamie revealed a potential hand injury and also stated she wanted to grant Holm (10-3) an immediate rematch. Holm has since been booked to another fight on June 17.
Justino, 31, has been campaigning to fight at UFC 214 on July 29 in Anaheim. She was cited for misdemeanor battery last weekend in Las Vegas, stemming from an alleged incident involving UFC strawweight Angela Magana.
UFC president Dana White told ESPN.com earlier this week that the promotion intends to gather all legal information regarding that case before booking the Brazilian's next fight.