Earlier this week, an algorithm made an absurd choice. Google AdSense, Google’s advertising program that makes up the bulk of the tech giant’s advertising revenue, decided that a web page about a decades-old bill about sexual abuse was “adult content,” and wasn’t allowed to display ads anymore.

The page, which is at least six years old and contains strictly legislative information about a bill called the “Child Sexual Abuse and Pornography Act of 1986” on free legislative research and tracking website GovTrack.us, tripped the AdSense algorithm that decides what pages are allowed to run ads.

This single, very dry page being flagged as “adult content” is most likely a minor fluke in the AdSense algorithm, but it’s a perfect example of how a tiny tweak in the way a platform uses automation to enforce policies can send a ripple through seemingly-unrelated parts of the internet.

GovTrack founder Josh Tauberer told me in an email that the bill page was flagged by AdSense as “policy non-compliant” on Monday, with Google citing the page’s “violations” in a summary of the AdSense adult content policy. Here’s what Google told GovTrack:

As stated in our program policies, we may not show Google ads on pages with content that is sexually suggestive or intended to sexually arouse. This includes, but is not limited to: pornographic images, videos, or games; sexually gratifying text, images, audio, or video; pages that provide links for or drive traffic to content that is sexually suggestive or intended to sexually arouse

Needless to say, the GovTrack page in question contained none of these.

Tauberer said he submitted a request to review the violation, and got back “a prompt response” that the request to un-flag the page was denied. The page still can't run AdSense ads:

Google did not immediately respond to a request for comment.

Since it’s an old bill and is infrequently visited by GovTrack users, Tauberer said, this one page being put in ad-jail by Google is inconsequential to the site’s overall ad revenue. Last year, GovTrack had about 33 million pageviews and a total AdSense revenue of about $37,000.

“If Google were to expand its filtering or flag the whole site as noncompliant because of situations like this, that would be a big problem for us,” he said. “But there's no reason to think that's going to happen.” It’s the first time he can recall getting a violation notice, and the only violation on the site right now.

It’s a similar problem as what social media platforms are encountering: Algorithms that try to wrangle user-generated content with bizarre, sometimes disastrous consequences. Facebook recently announced that it would uses algorithms to decide what makes a political ad, and it’s already messing that up. Algorithms are influenced by the humans that make them, but they aren’t human—and sometimes important nuance, like the difference between actual pornography and a legislative bill about pornography, are still lost on them.

“The whole business model is automation, and with automation you lose judgement in edge cases,” John Wonderlich, executive director at the Sunlight Foundation, told me in a phone call. And the repercussions of a misguided algorithm could bleed into censorship of what people see beyond ads, he said. “You wonder, for example, whether the same filters that removed GovTrack’s ad on that specific page, whether they might de-prioritize a search result on congress.gov for a bill about the same topic,” Wonderlich said. “Is our information infrastructure going to work properly when we’re trying to understand difficult topics? That would be a risk as well.”

This demonetization of one web page is just the tip of the advertising revenue iceberg, and while Google keeps publishers in the dark about how AdSense algorithms work, it’s difficult to say what tipped this one off. Someone might have linked to the bill page elsewhere, or Google made a slight change to the weight of keywords like “sexual,” but something triggered the flag after six years of nothing.