Facebook’s head of safety said on Tuesday a bug was responsible for posts on topics including coronavirus being erroneously marked as spam, prompting widespread complaints from users of both its flagship app and photo-sharing app Instagram.

“This is a bug in an anti-spam system, unrelated to any change in our content moderator workforce,” Guy Rosen, Facebook’s vice president for integrity, said on Twitter.

“We’ve restored all the posts that were incorrectly removed, which included 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,” he said.

Facebook users shared screenshots with Reuters of notifications they had received saying articles from prominent news organizations including Axios and The Atlantic had violated the company’s community guidelines.

One user said she received a message saying “link is not allowed” after attempting to post a Vox article about the coronavirus in her Instagram profile.

The issue arose a day after Facebook announced that it was sending home for public health reasons all contract workers who perform content review services for the social media giant, which mostly outsources the work to independent companies.

“We believe the investments we’ve made over the past three years have prepared us for this situation,” Facebook wrote in a blog post announcing the move, adding it would increase its reliance on “proactive detection” to remove violating content.

“That said, there may be some limitations to this approach and we may see some longer response times and make more mistakes as a result,” the post said.

Reuters