fuente Says Maks Chmerkovsky and Vanessa Lachey Have Been Bickering Since día One 

Erin Andrews revealed Maksim Chmerkovskiy sat out Monday night’s episode of 

due to “a personal issue” (sources tell PEOPLE it was

over a conflict with partner Vanessa Lachey due to their “big personalities”), but now a DWTS rep confirms he’ll be back in his dancing shoes for next week’s Most Memorable Year theme.

Still, an insider says that doesn’t mean Chmerkovskiy and Lachey (whose spouses are also paired on the reality competition) have resolved all their problems.

“They’ve been bickering since week one and he finally just had enough of it,” the source tells PEOPLE.

“They aren’t the first couple to have issues on

and they won’t be the last,” the source adds. “The pros are just as, if not more, popular than the stars when it comes to

fans, and Maks is one of the show’s most recognizable faces. They definitely will want him and Vanessa to play nice for the camera, but I wouldn’t expect them to last long if they don’t find a way to actually work together.”

This isn’t the first time Chmerkovskiy, 37, has butted heads with his 

 of his season 13 partner, soccer star Hope Solo, “That’s literally the only person that I could dislike from my past, present or future.”

Meanwhile, he and Lachey, 36, have both complimented Alan Bernsten for filling in Monday.

“Thank YOU to @alanbersten and my new girl posse, the @dancingabc girls troop, @brittbenae@hayley.erbert @dance10jenna!!! This was the ULTIMATE guilty pleasure! #GirlsNight,” Lachey captioned an Instagram of their performance. “Don’t forget to vote! (Link in my Bio!) 😘 I can’t WAIT to get started tomorrow with @maksimc on week 4! We’re cookin up something special for you!”

Thank YOU to @alanbersten and my new girl posse, the @dancingabc girls troop, @brittbenae @hayley.erbert @dance10jenna!!! This was the ULTIMATE guilty pleasure! #GirlsNight Don't forget to vote! (Link in my Bio!) 😘 I can't WAIT to get started tomorrow with @maksimc on week 4! We're cookin up something special for you!

Thank you @alanbersten for doing a great job stepping in for me…..again! #DWTS

Chmerkovskiy also posted a photo from the routine, simply writing, “Thank you @alanbersten for doing a great job stepping in for me…..again!”

Performance Due to a \'Big Chemistry Issue\' With Partner Vanessa Lachey, Says Source

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