CF (like many other companies) are responsive only when the complaint is posted on HN. Regardless, the issue wasn't solved, it came back within a few hours.

I've tried raising this issue on their forum, where I've failed to get the attention of the engineering teams, and while posting the ray ID should be sufficient, all you'd really get is clueless, unpaid volunteers asking you questions in circles like "what website do you see this on" (everywhere), "are you using adblock" (no, and Adblock has never blocked their Turnstile scripts) and "what's your user agent?" (the default Chromium one).

If I had to hazard a guess, it's their bot management script seeing "Linux" in the user agent and detecting missing video codecs (which is par for the course for standard Chromium builds), and thinking it's a headless browser. Between the the fact that differences between the JS runtime of Chromium and Chromium headless are very small these days, and the ClientHello permutation has destroyed bot management vendors' ability to distinguish different browser builds, they decided blocking all Linux users using Chromium was fair enough.