Corey Simms and his ex-wife, Leah Messer, appeared to be on good terms during Monday's episode of Teen Mom 2, but a short time later, Simms requested a judge return his title of primary custodian of their twins.

During Monday's show, Messer was seen regaining 50/50 custody of her and Simms' twins, Ali and Aleeah, 6, but according to a new sneak peek, she may not have joint custody for much longer.

"Leah Messer didn’t celebrate her custody win for long. After winning 50/50 custody of her twin daughters with Corey Simms, her ex-husband filed to be primary custodian – again!" Radar Online reported on Thursday.

According to the report, "Simms filed because West Virginia law does not recognize joint custodian and because Ali and Aleeah, 6, go to school in his district."

In Oct. 2015, Simms was named as the twins' primary custodian after a judge deemed him to be better suited for the twins. In addition to having time to help parent the twins, Simms is also married to wife Miranda, a stay-at-home mom. However, months later, the two returned to court where 50/50 custody was established.

At that point, Simms and Messer's custody battle was believed to be over, but now, judging by the new sneak peek, fans could be headed for even more drama as the seventh season of the show continues.

"Does Simms have a cause for concern? Throughout the season, fans have bashed Messer for her bad mom ways when she was caught on camera texting and driving. She also came under fire when she refused to feed her daughters breakfast before school," Radar Online pointed out.

Messer also has another daughter, Adalynn, from her previous marriage to Jeremy Calvert, and the former couple is believed to be sharing custody of the three-year-old, although an official custody agreement may not be in place.

For more of Corey Simms and Leah Messer, tune into Teen Mom 2 season seven on Monday nights at 10 p.m. on MTV, and check out a sneak peek of the upcoming episode below.

Tags: leah messer Corey Simms Teen Mom 2 MTV Reality TV Miranda Simms