During our regular reviews to ensure the accuracy of our systems, we recently found and fixed a bug that misattributed some clicks on video carousel ads as link clicks. This bug occurred when people were on mobile web browsers on smartphones — not on desktop or in the Facebook mobile app.
The bug affected billing only for the following conditions: for the video carousel ad unit; when the advertiser chose to bid on link clicks; and only for people who were on smartphone web browsers. In these cases, instead of being billed only for link clicks (clicks to an advertiser’s …Read More
Source:: Video Carousel Ads on Smartphone Mobile Web