'Sister Wives' star Christine Brown says the family puts 'problems and issues' aside during Christmas in an exclusive clip from the upcoming episode

• The Brown family celebrates Christmas in a clip from Sunday's new "Sister Wives."
• Christine says the family forgets about their "problems and issues" to celebrate the holiday.

The Brown family gathers at Robyn's house for Christmas in a clip from Sunday's upcoming episode of "Sister Wives," but not everyone is feeling joyful.

In TLC's sneak peek, some family members are feeling the holiday spirit and choosing the focus on the positives.

"Overall, I'd say our Christmases are always really good," Christine Brown says in a solo interview seemingly filmed in December 2020. "We just kind of put whatever problems and issues individuals will be having — we just kind of put those aside and just tackle that on another day."

She also says the family tries to "just focus on celebrating us together," reflecting on how their holiday in 2020 was "a great Christmas."

Ultimately, that good spirit didn't last into the 2021 holiday season. Christine, who is Kody's third wife, announced their split in November via Instagram, writing that they "have grown apart" and that she made "the difficult decision to leave."

Robyn adds in the clip from Sunday's upcoming episode, at which point Christine and Kody were seemingly still in a relationship, that having the whole Brown family together at Christmas was "melting away some of the hurts" between family members.

But not everyone is feeling merry and bright in the clip.

Much of this season of "Sister Wives" has shown tension between Kody and his wives as the polygamous patriarch has pushed to get every member of his family who lives on their property in Flagstaff, Arizona, to follow his strict COVID-19 safety rules.

"I think we've damaged some relationships. So I think it's time to get back to the normalcy and see if we can smooth some of those things out," Janelle says of the family's Christmas celebration in the preview.

Kody similarly mentions the struggles the family has had throughout the year with relationships, COVID-19, and the death of Janelle's mother, Sheryl Brown, who was married to Kody's dad, William Winn Brown, until William's death in 2013.

"I'm a little blue. I'm not really feeling that joyful this Christmas," Kody says.

The clip also shows the toll COVID-19 separation took on other members of the family. Kody and Robyn's daughter and the youngest Brown child, Ariella, appears to forget some of her older siblings' names while opening gifts from them.

"It's interesting, and it's even a little sad, that Ariella is forgetting who her brothers and sisters are," Kody says.

A new episode of "Sister Wives" airs Sunday at 10 p.m. ET on TLC.