As the Notre Dame Cathedral went up in flames on Monday, YouTube flagged livestreams of the incident as possible sources of misinformation and then started showing people articles about the 9/11 attacks.
The cause of the fire was not immediately known, but it broke out as the 12th-century cathedral was undergoing a multimillion dollar renovation project. Police in Paris also said no deaths were reported from the site.
Several news outlets quickly started livestreaming the fire on YouTube. However, underneath several of them was a small gray panel titled "September 11 attacks," which contained a snippet from an Encyclopedia Britannica article about 9/11.
The feature is part of a larger rollout of tools and disclaimers to prevent users from consuming misinformation on the platform.
If a user clicked the gray box, they would be taken to the full article about the US terror attack.
BuzzFeed News found at least three livestreams of the Notre Dame fire from major news outlets with the 9/11 disclaimer. The disclaimer was then removed, one by one, after several minutes. But by then, Twitter users had taken notice.
It's unclear how the Notre Dame livestreams triggered the panel, but a spokesperson for YouTube said the "information panels" with links to third-party sources like Encyclopedia Britannica and Wikipedia are activated by an algorithm.
"These panels are triggered algorithmically and our systems sometimes make the wrong call," the spokesperson added. "We are disabling these panels for livestreams related to the fire."
According to a link inside the disclaimer, the information panel is a feature that is currently only available to users in the United States and South Korea. The help page adds that the panel will appear alongside videos related to the topic, regardless of opinions or perspectives in the footage.
The moderation of YouTube livestreams has been a problem for the platform.
Last week, during a congressional hearing on white nationalism and social media, YouTube's moderators had disabled comments on livestreams of the hearing because the comment sections became so racist. One stream of the hearing by Swedish white nationalists was even able to be monetized, with commenters using the Super Chat feature to donate money to the channel as it streamed.