The feature allows Facebook users in danger zones to mark themselves as safe, but this time it was triggered by a protester throwing firecrackers, the BBC reported.
Facebook said it relied on a “trusted third party to confirm the incident” but the feature misled many online as people started sharing false news of a blast.
Facebook has recently faced criticism for allowing fake news to proliferate.
On Tuesday, a protester threw small firecrackers at a government building in Bangkok.
According to Facebook, this triggered the Safety Check feature around 9.00 p.m. and created a page titled “The Explosion in Bangkok, Thailand”, and people started marking themselves as safe.
The page also pulled in a link from a website called bangkokinformer.com referencing a BBC breaking news video about an explosion in the capital, but the video was, in fact, taken in 2015 in reference to a blast at the Erawan shrine.
According to a BBC journalist, the first he knew something was wrong was a stream of messages asking if he was ok, and spotting friends marking themselves as safe in Bangkok.
“By the time my colleagues had made efforts to get the erroneous post taken down, it had circulated widely, within minutes,” the journalist said.
It turned out Facebook was generating an automatic request to people to declare themselves safe, so even experienced journalists, who would have realised the story was not genuine, inadvertently gave it some credence by responding to the Facebook prompt, the BBC said.
When Facebook first introduced the safety feature tool in 2014, it would activate the feature manually.
In November, Facebook changed course and said it would now be activated “by our community”.
Now, a third-party source alerts Facebook when an incident occurs. The social platform then searches to see if users in the area are discussing the incident.
If enough users are referencing the incident, those in the area are invited to mark themselves as safe.
According to Facebook, the title of the safety check is taken from the alert provided by the third-party source.