Why has the search system broken the “Back” button?

The interface to https://hn.algolia.com has changed, again, and now the back button is broken.

You're making it more and more annoying with every change. Please, stop it.

(No doubt I'm in a minority and everyone else loves it, but I do wonder whether you actually do any user testing, or if you just implement stuff because you think it's cool, and just honestly don't really care.)