Be extra careful when setting up or editing remarketing campaigns. This can happen to you, too.
If you select a website custom audience these days, Facebook will automatically turn on Advantage Custom Audience, which gives them the ability to expand your audience beyond the target group. You may not want this when remarketing.
While I caught this when setting up the campaign originally, I had to make a minor edit to the custom audience after it started running. When I did that, I didn't notice that Facebook AGAIN turned Advantage Custom Audience on, expanding the audience.
This was kind of messed up since the campaign was a very specific message for a very specific (and small) group. Within hours, I became suspicious because the ad started getting more engagement and some weird comments.
I caught it, but not until the ad reached more than 60,000 people it wasn't supposed to reach. Kind of insane, but it happened.
Personally, I find this problematic that such a setting gets turned on automatically after the original ad set had it turned off. It's misleading and will cause issues for advertisers.
Watch out!
