Ask HN: Why does CamelCamelCamel search redirect to Project Gutenberg?

The search box on the website (https://camelcamelcamel.com) works fine but directly visiting the search URL sends you to a Cloudfront cache of Project Gutenberg (specifically The Adventures of Sherlock Holmes).

Playing with it via curl, seems like omitting the Referer header causes it:

This goes to Gutenberg:

    curl -v https://camelcamelcamel.com/search?sq=test

This doesn't:

    curl -v https://camelcamelcamel.com/search?sq=test -H 'Referer: https://camelcamelcamel.com/'

Any ideas what's going on? Maybe they were being web scraped live via AJAX and put in a referrer check to break things? Problem with that is that it broke my quick search links...