In recent months, Facebook has repeatedly run into trouble for its algorithms failing to catch instances of hate speech. Another dramatic example occurred this week when a reporter from The Guardian saw an ad for Instagram on Facebook that prominently featured a screenshot of a rape threat.

The screenshot had been shared by reporter Olivia Solon on her Instagram page, and because it was one of her most engaged-with posts, Facebook used it as an example to advertise Instagram. (It’s also worth noting that Facebook owns Instagram.) Solon’s screenshot was of a hateful email she’d received from someone threatening to rape her. What’s worse, the ad featuring Solon’s screenshot popped up on her own sister’s feed.

Instagram issued a statement apologizing for the incident, but also downplayed it, claiming not many people actually saw it.

“We are sorry this happened—it’s not the experience we want someone to have,” an Instagram spokesperson said. “This notification post was surfaced as part of an effort to encourage engagement on Instagram. Posts are generally received by a small percentage of a person’s Facebook friends.”

It’s putting it lightly to say this isn’t an “experience” someone would want to have. Hopefully Facebook and Instagram figure out a way to better screen out this kind of mistake in the future.