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Alessio Jacona / Flickr cc

Facebook conceded Tuesday that it recently found and fixed a bug that "misattributed some clicks" on video carousel ads as link clicks. The bug occurred on mobile web browsers on smartphones, which drive significantly less traffic to Facebook than mobile app or desktop. Facebook says it will refund all impacted advertisers in full.

This is not an isolated incident. Per MarketingLand, this is the 10th time Facebook has conceded a measurement mistake to advertisers since September, when it revealed it had overestimated video metrics by up to 60% for two years.

Why it matters: The news comes just months after Facebook agreed to be audited by the de facto media watchdog, the Media Ratings Council (MRC), a move that other "walled garden" social platforms, most notably Twitter and Snapchat, have yet to make. The incident proves that although Facebook has taken many steps, including the audit, to ensure accurate measurement and reliability to its ad partners, it's nearly impossible to get it right 100% of the time at its scale.

Go deeper

Updated 4 mins ago - Politics & Policy

Inauguration Day dashboard

U.S. Capitol and stage are lit at sunrise ahead of the inauguration of Joe Biden. Photo: Patrick Semansky - Pool/Getty Images

President Biden has delivered his inaugural address at the Capitol, calling for an end to the politics as total war but warning that "we have far to go" to heal the country.

What's next: Biden has arrived at the White House and he will sign executive orders and other presidential actions.

32 mins ago - Podcasts

Podcast: After the Biden inaugural

Joe Biden was sworn in today as America's 46th president in an inauguration unlike any other in modern history.

Axios Re:Cap goes deeper into the speech, the atmosphere and what it all tells us about the incoming administration, with Axios political reporters Hans Nichols and Alexi McCammond.

Biden embarks on a consequential presidency

Photo illustration: Sarah Grillo/Axios. Photo: Joe Raedle/Getty Images

Donald Trump tried everything to delegitimize the rival who vanquished him. In reality, he's set Joe Biden on course to be a far more consequential U.S. president than he might otherwise have become.

The big picture: President Biden now confronts not just a pandemic, but massive political divisions and an assault on truth — and the aftermath of the assault on the Capitol two weeks ago that threatened democracy itself.