Liberal presidential contender Sen. Elizabeth Warren is set to take part in a candidate forum Monday in Iowa on issues affecting Native Americans, and participants say it will be hard to ignore the Massachusetts Democrat’s questionable claims of having tribal ancestry.

“It’s going to be awkward for her even if she puts on a smile,” said Simon Moya-Smith, a 36-year-old Native American activist.

Moya-Smith, of the Ogala-Lakota Nation, wants Warren to address the controversy, sparked after the Massachusetts senator claimed her mother was “part Cherokee and part Delaware” in 2012, then released a DNA test showing she was between 1/64th to 1/1,024th Cherokee.

“I think she should apologize. I think she owes an apology to all natives. Just own it. Own that you’re not native,” Moya-Smith said.

“Nobody has ever called her an injun. Nobody has ever called her a redskin. Nobody has ever called her a prairie N-word. That’s not her identity. She doesn’t have to live it. We do.”

Warren has dubbed “Pocahontas,” by President Trump, who has used the name to mock her ancestry claim.

The issue hasn’t come up during either of her two presidential debate appearances, and TV anchors have yet to grill her about it.

But the flap remains a sensitive subject for nation members.

“It’s a big deal in some circles for sure,” said Christine Nobiss of Global Indigenous Council Seeding Sovereignty, which is co-hosting the Frank LaMere Native American Presidential Forum in Sioux City.

“We have a panel of quite a few native American leaders in the country that will be there to ask her questions. I wouldn’t be surprised if it came up.”

Warren, who was rebuked by the Cherokees and apologized to the nation in February, is scheduled to take the stage at 10 a.m. in front of more than a dozen Native American advocacy organizations, and the event will kick off with a rendition of the National Anthem sung in Lakota.

She’ll be joined by Bernie Sanders, Marianne Williamson, Steve Bullock, John Delaney, Amy Klobuchar, Julián Castro, Bill de Blasio and the Navajo Nation’s Mark Charles.

The matters set to be discussed include voting rights for Native Americans, violence against indigenous women and a bill known as the “Remove the Stain Act,” which would revoke the medals of honor awarded to soldiers who took part in the 1890 massacre at Wounded Knee.

More than 1,200 people have signed up to attend.