In April of this year, former late night host Jay Leno visited NBCUniversal in Los Angeles to appear as a guest judge on the network’s unscripted program “America’s Got Talent,” a variety show that seeks out undiscovered musicians, performers and other quirky artists.

On the second floor of a production building on the North Hollywood lot, Leno taped an interstitial segment in the presence of show judges including Gabrielle Union and Julianne Hough. While taping, Leno made a crack about a painting on display in a hallway of Simon Cowell, the show’s executive producer and judge, surrounded by his dogs. Leno joked that the pets looked like something one would find “on the menu at a Korean restaurant,” four people present for the taping told Variety.

Individuals at the long-running program found the joke to be offensive — especially for what one insider described as “the very few Asian staffers” employed by the show, one of whom was present when Leno spoke the line directly to camera. The joke was viewed as perpetuating stereotypes about Asian cultures consuming dog meat.

Union, a new hire for the 14th season of “America’s Got Talent,” urged producers to report the joke to human resources at NBC, multiple insiders familiar with the show said. Her argument was that production needed to understand why the joke might offend the staff and audience of “AGT,” according to three people who overheard conversations with Union and producers. The issue of reporting to human resources was specifically raised with an NBC executive on set, but several insiders said it was never escalated to that department.

The line was cut from the episode when it eventually aired on August 6.

However, the Leno incident is one of several examples of what insiders called a toxic culture at the show. The season concluded with NBC deciding not to renew the contracts of Union and Hough, sources said, both of whom could have been renewed for another season under their contractual options.

“‘America’s Got Talent’ has a long history of inclusivity and diversity in both our talent and the acts championed by the show,” NBC and series producer Fremantle said in a joint statement. “The judging and host line-up has been regularly refreshed over the years and that is one of the reasons for AGT’s enduring popularity. NBC and the producers take any issues on set seriously.”

Union declined to comment on the matter. Representatives for Simon Cowell’s Syco Entertainment had no comment. A spokesperson for Jay Leno did not return Variety’s request for comment.

Variety exclusively reported on Friday that both Union and Hough were cut from the show, and that Cowell and cast members Howie Mandel and Terry Crews were all expected to return. At the time, an NBC insider described the parting of ways as amicable.

Yet Union and Hough were also said by sources to have received excessive notes on their physical appearance. Two insiders familiar with the set said Hough had received consistent criticism on hair, makeup and wardrobe, which impacted her morale and led to tensions. Hough denied this in a statement to Variety as not accurate to her experience.

“I had a wonderful time on ‘America’s Got Talent,’ I loved working with the cast, crew and producers. I am happy to continue my working relationship with NBC,” she said. She also expressed excitement for two upcoming NBC shows she’ll be featured in, “Holidays With the Houghs,” costarring her brother Derek, and “Christmas in Rockefeller Center” in December. “I’m looking forward to what the future holds,” she added.

Union was subjected to a very specific critique — that her rotating hair styles were “too black” for the audience of “AGT,” a note she received over half a dozen times, according to four sources with direct knowledge of the exchanges who spoke on the condition of anonymity. One network insider disputed the volume of notes, saying there was only feedback about hair continuity for both judges.

This would not be the first time “AGT” has been accused of insensitivity towards top talent. Nick Cannon, who hosted the series for seven seasons, resigned abruptly in 2017 in a scathing Facebook post that condemned NBC.

In a standalone comedy special for Showtime, Cannon made a joke about “AGT’s” squeaky-clean image, saying he could no longer use the N-word in his routine. Cannon said NBC attempted to retaliate when they caught wind of the bit.

“I was to be punished for a joke … My soul won’t allow me to be in business with corporations that attempt to frown on freedom of speech, censor artists, and question cultural choices,” Cannon wrote. “Not to get too detailed but this isn’t the first time executives have attempted to ‘put me in my place’ for so-called unruly actions.”

Sources also shared a related incident that occurred during another audition taping this season, where Union and other staffers expressed concerns over a white male performer crossing a line in portraying people of color. The contestant’s gimmick involved rapid costume changes inside a larger garment, while impersonating a multitude of famous singers. In one such quick change, the contestant emerged in the guise of Beyoncé Knowles. His hands appeared as black, meant to be a character accent, three witnesses to the audition said.

Union immediately recommended to a segment producer and an executive producer that the contestant be removed from the lineup, sources said, adding that the producers disagreed and used a familiar refrain heard on the “AGT” set: “We’ll take it out later.”

Union pressed further, said another individual, saying the show’s live audience should not be subjected to something racially insensitive. The producers who Union spoke to sent the performer to the stage and his live audition was later cut from the episode, added the insider. NBC and Fremantle declined to comment on the matter.

Following news of their departure, speculation began almost immediately about the nature of the cast decisions. Entertainment writer B. Scott reported over the weekend that Union had taken issue with “problematic” situations and was terminated as a result. An NBC insider reiterated an assertion from Variety’s report that hosts are rotated in and out with options to return.

Despite seeing a ratings decline for at least three years, the show’s social media presence has doubled since Union and Hough replaced longtime female judges Melanie Brown (of Spice Girls fame) and model-host Heidi Klum. The 18-episode season that wrapped in September generated 25 million social media impressions, approximately half of which engaged directly with Union, according to figures from Nielsen Social, effectively making her the most popular judge.

This year’s “AGT” finale drew approximately 10 million viewers, down three million from the year before but top rated in the 18-49 demographic.