Nickelodeon’s Nicky, Ricky, Dicky & Dawn is down a quadruplet. Mace Coronel, aka Dicky on the hit live-action comedy series, has left the show, making its future beyond Season 4 uncertain.

A Nickelodeon spokesperson says the network and Coronel “mutually parted ways” during the summer, noting that “it was a mutual decision” and a decision has not been made on Season 5.

There has been no further comment from either side but I hear that that had been simmering tensions on the set of the sitcom for awhile and growing issues and personality conflict among the young cast. They came to a head toward the end of production on the upcoming fourth season, with the network and Coronel abruptly severing ties in August with around around five episodes left to film from the show’s 14-episode fourth season. Production was completed without him, wrapping on Sept. 22 for a 2018 premiere.

Coronel revealed he’d left the show in an Instagram post last month and noted that the photo was taken on the set of a new film he’s working on. “I wanted to announce that as of 3 weeks ago I’m off Nicky Ricky Dicky Dawn!,” he wrote on September 10. “I made a mutual agreement with Nickelodeon and the show is going on without me, and I’m so excited to be back acting in some serious and more diverse projects.”

The series, which premiered on September 13, 2014, has been a consistently strong ratings performer for Nickelodeon. The most recent 24-episode Season 3, which concluded its run on August 5, was up 4% vs. Season 2 with kids 2-11 and 6-11, according to the network, and Nicky, Ricky, Dicky & Dawn finished the most recent quarter as Nick’s top-rated series. While Nicky, Ricky, Dicky & Dawn is one of Nickelodeon’s top performers, sources indicate it would be very hard — or even unlikely — for the comedy to continue without Coronel.

Nicky, Ricky, Dicky and Dawn follows the adventures of the 12-year-old Harper quadruplets, Nicky (Aidan Gallagher), Ricky (Casey Simpson), Dicky (Coronel) and Dawn (Lizzy Greene), who don’t have much in common except their birthday but know they can do anything when they stick together.

Michael Feldman, who developed the comedy with Matt Fleckenstein, served as executive producer and showrunner for all four seasons. Fleckenstein stepped down as executive producer after Season 2, segueing to a consultant capacity.