Monday night’s episode of “The Bachelor” seemed to be going well, drama and head injuries aside. The contestants dating this season's eligible man, Peter Weber, spent a group date modeling for a Cosmopolitan magazine photo shoot in the Costa Rican jungle. They picked out swimsuits, posed alongside a scenic backdrop of trees and waterfalls — and one woman, Victoria Fuller, was chosen to adorn the magazine’s March cover.

And then, trouble in paradise.

The magazine — in a letter from the editor, Jessica Pels, posted minutes after scenes from the date aired — said it would not publish the cover with Ms. Fuller, citing an ad campaign in which she modeled “White Lives Matter attire.”

“Unequivocally, the White Lives Matter movement does not reflect the values of the Cosmo brand,” Ms. Pels wrote. “We stand in solidarity with Black Lives Matter, and any cause that fights to end injustices for people of color.”

When “The Bachelor” premiered in January, photos circulated on Twitter showing Ms. Fuller, 26, a medical sales representative from Virginia Beach, Va., posing in a blue “WLM” hat. Other apparel from the same, now-defunct Instagram account featured an altered version of a Confederate flag — which, in place of stars, featured tiny fish — the words “White Lives Matter” and a web address: “MarlinLivesMatter.com.”