Advertisers are pulling promoted tweets from Twitter after discovering their ads were being displayed on porn and other X-rated profile pages on the popular social media platform.

Twitter supposedly had a filter that would prevent promoted tweets from being displayed on any inappropriate content, including porn. Nielsen, the digital and television data company, was the first advertiser to become aware of the inappropriate ad placement and they were understandably upset to discover that their promoted tweets were showing up on these porn profiles when people are viewing them.

This wasn’t an issue exclusive to Nielsen. AdWeek noticed other advertisers including Gatorade and NBC Universal.

Twitter is aware of the issue and is currently working on a fix, although a timeline for it to be implemented is unknown.

“We’re aware that Promoted Tweets are being displayed on some profiles that contain inappropriate content,” a Twitter spokesman said in a statement to Adweek. “We are committed to providing a safe environment for brands to build their business, and our product team is working to fix the issue.”

The ads are usually targeting a specific person as they view profiles on Twitter, so it wasn’t that Twitter was deliberately placing ads on these x-rated profiles, it is simply that the person the ad was targeting happened to view those profiles and content.

This issue has probably been going on for some time, so it likely isn’t brand new.  But for advertisers to be aware of the issue requires someone admitting they were on a porn profile when they noticed the ad – and not surprisngly, not many people were voicing the problem.

While other advertising platforms have definitely had their own problems with ads appearing on inappropriate content, because Twitter actually host the content themselves, it’s kind of surprising that they are not at the very least using keyword filters to prevent promoted tweets from being displayed on these profiles. Even at a most basic level, you would think that Twitter would include the word “porn” in a username or handle as a filter to prevent ads from showing up on that profile, especially for advertisers that would likely object to the placement.

Until a fix is in place, promoted tweets will likely continue to be displayed on inappropriate profile pages.