facebook advertisers being misled about the effectiveness of facenbook ads? Yes, infamously so.
2016 video numbers scandal:
https://ia.acs.org.au/article/2019/facebook-to-pay--60m-for-fake-video-stats.html
"potential reach" metric lawsuit:
https://www.theverge.com/2021/2/18/22289232/facebook-ad-revenue-proposed-reach-inflation-lawsuit-unredacted-filings