Facebook has repeatedly run into trouble in recent months for removing controversial live video streams. First, the site temporarily removed footage of the aftermath of a fatal police shooting in Minnesota, and then it took down video being shot by an African American woman in the middle of a standoff with police. Now, Facebook stands accused of censoring video shot by activists protesting the Dakota Access pipeline in North Dakota.

The video, which was shot by the media collective Unicorn Riot, shows police arresting a large group of protesters at the controversial pipeline. Facebook later apologized for removing the video and said an automatic spam filter had accidentally caught it, but the activists behind the video weren’t buying it.

“At a critical moment of our coverage of a Dakota Access Pipeline direct action today, Facebook’s automated censorship system blocked our video URL, shortly before two of our journalists were arrested onsite,” a Unicorn Riot collective member wrote in an email statement. “Both Facebook and law enforcement acted to block our media distribution today, but we will not let them stop our mission to amplify the voices of people who might otherwise go unheard, and broadcast the stories that might otherwise go untold.”

Even if it was a misunderstanding like Facebook says, incidents like this one seem to keep adding up — and they do not reflect well on the site.