Facebook Inc. said a filter for combating spam on the social network was beset by a bug that mistakenly eliminated legitimate news stories and other posts, miscategorizing them as content that violates its rules.

Several users complained on social media that their posts, including those about the novel coronavirus outbreak, were taken down and replaced by a notice that read, "This post goes against our community standards on spam."

In response, Guy Rosen, Facebook's vice president of integrity, said in a Twitter post that it was a bug in an anti-spam system. Later he tweeted that all content that was incorrectly removed had been restored, including "posts on all topics — not just those related to Covid-19. This was an issue with an automated system that removes links to abusive websites, but incorrectly removed a lot of other posts too."