Facebook Inc.’s overzealous spam filter temporarily put a lid on some coronavirus links.

A bug in its News Feed prevented URLs from legitimate sources such as USA Today and BuzzFeed from being shared as posts or comments Tuesday. Many Facebook FB, -0.89% members like Lana Rushing, who runs a public-relations company in Los Angeles, said she received a warning from Facebook after attempting to share news posts on the pandemic from USA Today and NBC’s Today Show.

“All of the sudden, I began receiving notifications from Facebook for posts that I shared, saying they violated community guidelines, marking them as spam,” Rushing told MarketWatch in a Facebook message Tuesday. “When I disputed these reports, Facebook overrode my request and began closing the cases.”

The notifications referred to posts previously shared with Rushing’s network of Facebook friends, she said. This marks the first time Rushing said she was warned of violating the social network’s community standards on spam in the 13 years she’s been a member.

In a tweet late Tuesday, Guy Rosen, vice president of integrity at Facebook, said, “We’re on this — this is a bug in an anti-spam system, unrelated to any changes in our content moderator workforce. We’re in the process of fixing and bringing all these posts back. More soon.”

He followed that up about an hour and a half later with a tweet: “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.”

The spam glitch comes a day after Facebook, Twitter Inc. TWTR, +2.03% , Alphabet Inc.’s GOOGL, -2.41% GOOG, -2.37% Google and YouTube, Microsoft Corp.’s MSFT, -1.24% , LinkedIn and Reddit issued a joint statement saying they had partnered to fight the spread of fraud and misinformation on the COVID-19 outbreak.

See also: Facebook, Twitter, Google and other tech giants join forces to fight coronavirus fake news

Most coronavirus-related links did make their way through Facebook, including posts from MarketWatch and other news organizations like CNN.