Facebook got fooled by its own algorithm. Today, the social network activated its Safety Check feature but falsely suggested that there was an explosion in Bangkok, Thailand.

Users in the country saw an alert to mark themselves safe, but saw little details about when or where in Bangkok the “explosion” occurred. Safety Check came on at around 9PM local time and was deactivated about an hour later. News that “reported” the explosion linked back to an outdated story on Bangkok Informer about the 2015 Erawan Shrine bombing.

So what actually happened? Here’s Facebook’s statement to The Verge on the matter.

“Safety Check was activated today in Thailand following an explosion. As with all Safety Check activations, Facebook relies on a trusted third party to first confirm the incident and then on the community to use the tool and share with friends and family.”

According to BBC, an incident occurred in the nation’s capital where a man threw ping pong-sized firecrackers that resembled explosives at a government building. Facebook claims this separate incident prompted Safety Check to turn on.

Though there were no explosions, the event page for this particular Safety Check was titled “The Explosion in Bangkok.” Additionally, there were no links to the original news story listed. Instead, the three linked stories, as shown in the screenshot above, cite the 2015 explosion, and a blog post that roughly translates to “When your friend digs up news about a bombing that happened a year ago to share on Facebook, so very annoying.”

Facebook is looking into how these unrelated links were added to today’s Safety Check page.

In November, Facebook announced that its Safety Check feature will be triggered by an algorithm that looks at trending posts by users in an area and give them an option to enable the feature. At the time, I spoke to Peter Cottle, a Facebook engineer who helped create Safety Check, about the possibility of false positives. Cottle assured that the algorithm uses third-party enterprise software to fact check the event before turning Safety Check on.

This isn’t the first time Safety Check experienced a mix-up; in March, Facebook alerted users in the US, UK, and other countries to mark themselves safe after a bombing in Pakistan.

(The Verge)