NEW YORK: YouTube and Facebook have faced difficulties recently around brand safety and measurement data, and neither appears to have completely resolved the issues, with some major advertisers yet to return to YouTube, and Facebook admitting to yet another metrics glitch.

In a blog post, Facebook reported that it had found and fixed a bug that misattributed some clicks on video carousel ads as link clicks.

It played down the significance of this, however, saying it had only occurred when people were on mobile web browsers on smartphones, not on desktop or in the Facebook mobile app – this last being most people's preferred option.

"The impact from a billing perspective was 0.04% of ads impressions," the post stated, adding that affected advertisers were being credited accordingly.

This is the latest in a string of measurement errors going back several months – ten since September last year, according to Marketing Land – but it is the first that has had the effect of advertisers being wrongly charged.

The sums involved aren't great, however: the same title cited "a person familiar with the matter" claiming the median amount of money that individual advertisers are being refunded is $10.

Keith Weed, Unilever CMO, welcomed Facebook's transparency but added: "It highlights once again that while there has been progress, there is still further improvement needed."

That sentiment would seem to apply equally to YouTube's efforts around brand safety. When Barron's Next contacted a dozen companies that had reportedly pulled their ads from YouTube and/or the Google Display Network, it found several major brands had yet to return, including Wal-Mart (to YouTube) and Nestle (to Google/YouTube).

Toyota, meanwhile, indicated it was currently running ads only on those channels where they could direct placement, such as Buzzfeed and Discovery.

In a related development, the IAB has published a paper – An Evolving Framework for Advertising Automation – to create clarity around programmatic functions and encourage more meaningful conversations among buyers, sellers, and technology vendors.

Data sourced from Facebook, Marketing Land, Wall Street Journal, Barron's Next, IAB; additional content by WARC staff