Usher and Chris Brown reportedly still at odds despite putting on a united front for fans

Two upcoming performances in Los Angeles and Miami have been canceled as questions about the singers’ working relationship continue.

Usher and Chris Brown may be sharing the stage, but apparently, they aren’t exactly getting along behind the scenes.

The R&B superstars’ joint tour is reportedly dealing with some serious interpersonal drama, with a source close to the situation telling PEOPLE that the relationship between the two singers has deteriorated to the point that they can barely stand each other.

In an exclusive report published Friday, PEOPLE detailed the alleged fallout, which reportedly intensified following a disagreement during the tour’s Atlanta stop earlier this month. According to the insider, the tension stems from longstanding personal differences, competing egos and disagreements over creative control.

The situation allegedly came to a head when the Atlanta concert began nearly two and a half hours late. Brown reportedly wanted to delay the performance because of heavy traffic around Mercedes-Benz Stadium, hoping to give fans more time to arrive. Usher, however, was reportedly frustrated with the delay and confronted Brown backstage.

The singers eventually appeared together onstage, performing several songs and exchanging hugs, giving fans the impression that any disagreement had been resolved. But according to PEOPLE’s source, the friendly display was largely for appearances.

“They were doing it for show,” the insider reportedly said, adding that the artists were still not speaking backstage.

The reported friction comes as two additional performances on the joint R&B Tour have been canceled. The Nov. 16 show at SoFi Stadium in Inglewood, California, and the Dec. 6 performance at Hard Rock Stadium in Miami are no longer moving forward. The source disputed speculation that poor ticket sales were responsible, instead pointing to the singers’ inability to work together.

Their Nov. 15 Los Angeles performance remained listed as of the report, although even members of their respective teams reportedly weren’t certain both artists would appear.

For now, the tour’s financial commitments and obligations to fans appear to be keeping the two performers on the same bill. Whether they can put their differences aside long enough to finish the run remains another question.