The only real one I can remember off the top of my head, where facebook giving access to data didnt turn out to be userbase hands over data on themselves and friend, was the Netflix and some others getting access to private messages. And even there, it wasnt nefarious, it was facebook trying to extend people features, like being able to send their friends spotify songs.

https://www.theverge.com/2018/12/18/18147616/facebook-user-d...