@raulinbonn @marcan That reporting was wrong.

It was people with adblockers, but the adblock code didn't catch everything related to the player for a short while. There's a short snippet that on normal playing delays the video for a few seconds to inject the ads. The filter lists caught the general ad script, but not the delay code.

Now of course, statistically speaking, a poorly configured adblocker will be more likely to affect Firefox users than Chrome users, but it wasn't specifically targeting Firefox users.