Three top consultants to the 2016 presidential campaign of Sen. Bernie Sanders (I-VT) are leaving his recently launched 2020 Democratic presidential bid over “creative differences.”

The strategists behind the media consulting firm Devine Mulvey Longabaugh— Tad Devine, Mark Longabaugh, and Julian Mulvey— told Sanders they would be parting ways with his 2020 campaign after helping him challenge former 2016 Democratic presidential nominee Hillary Clinton, New York Times reporter Jonathan Martin tweeted Tuesday.

NEWS: The architects of @BernieSanders media campaign in ‘16 have split from him. @MarkLongabaugh @julianmulvey @taddevine say they “are leaving because we believe that Sen. Sanders deserves to have media consultants who share his creative vision for the campaign” Story tk — Jonathan Martin (@jmartNYT) February 26, 2019

“There were differences in a creative vision,” Longabaugh told CNBC. “We want to leave on a very positive note, and we are proud of the work we’ve done on the campaign. It was just clear, however, that we weren’t in sync.”

Although Longabaugh cited creative differences as the reason his firm parted ways with Sanders, he declined to elaborate on those differences. The consultant added that he would be happy to advise Sanders in the future.

“I told the senator this morning that if he ever wanted to call on me for guidance, I would be glad to provide that. I think everybody was kind of sad about it,” he added.

Sanders’s 2020 campaign manager, Faiz Shakir, released a statement saying “the campaign appreciates all the good work DML had done and wishes them well.”

Devine, Mulvey, and Longabaugh were considered to be the group behind Sanders’ media strategy in his bid against Hillary Clinton in 2016. The Vermont senator eventually lost to Clinton.

Sanders officially launched his bid as a Democrat last week to run in the 2020 presidential election.