If a Facebook user blocks someone, there’s probably good reason for it. As Facebook itself notes, this is often because, at best, they find the content being shared annoying. However, blockings often occur for far more serious reasons, like bullying and harassment. So it was pretty troubling when Facebook revealed this week that a bug accidentally unblocked people for over 800,000 users. That means even though these affected users proactively blocked someone from viewing their content, that blocked individual could’ve found it anyway between May 29 and June 5.

Thankfully, this bug only applied to public posts. If affected users had their content set to private or only with friends, blocked individuals could not see it. However, if the settings were any broader than that, they could.

“While someone who was unblocked could not see content shared with friends, they could have seen things posted to a wider audience,” Erin Egan, Facebook’s Chief Privacy Officer, wrote in a blog post. “For example pictures shared with friends of friends. We know that the ability to block someone is important — and we’d like to apologize and explain what happened.”

While this is a relatively small issue compared to Facebook’s many other privacy problems, it’s still cause for concern. The company seemingly can’t stop itself from sharing user info with the wrong people.