YouTube’s new moderators, brought in to spot fake, misleading and extreme videos, stumbled in one of their first major tests, mistakenly removing some clips and channels in the midst of a nationwide debate on gun control.

The Google division said in December it would assign more than 10,000 people to moderate content after a year of scandals over fake and inappropriate content on the world’s largest video site.

In the wake of the Feb. 14 school shooting in Parkland, Florida, some YouTube moderators mistakenly removed several videos and some channels from right-wing, pro-gun video producers and outlets.

Some YouTube channels recently complained about their accounts being pulled entirely. On Wednesday, the Outline highlighted accounts, including Titus Frost, that were banned from the video site. Frost tweeted on Wednesday that a survivor of the shooting, David Hogg, is an actor. Jerome Corsi of right-wing conspiracy website Infowars said on Tuesday that YouTube had taken down one of his videos and disabled his live stream.

Shutting entire channels would have marked a sweeping policy change for YouTube, which typically only removes channels in extreme circumstances and focuses most disciplinary action on specific videos. But YouTube said some content was taken down by mistake. The site didn’t address specific cases and it’s unclear if it meant to take action on the accounts of Frost and Corsi.

“As we work to hire rapidly and ramp up our policy enforcement teams throughout 2018, newer members may misapply some of our policies resulting in mistaken removals,” a YouTube spokeswoman wrote in an email. “We’re continuing to enforce our existing policies regarding harmful and dangerous content, they have not changed. We’ll reinstate any videos that were removed in error.”