Why is Firefox sometimes playing audio tracks silently?

Recently (in the last month), I’ve found that Firefox plays audio tracks silently in some cases. It thinks it’s playing, and the track’s time will run down, but no sound will actually be produced.

I am using Firefox 150.0.2 (64-bit) on Windows 11 25H2 (26200.8328). I assume it depends on the website’s method for playing audio or on the format.

Examples:

Many similar websites (e.g. Spotify, YouTube, Duolingo) play just fine.

All examples are fine in other browsers, so I’m wondering if something is borked in Firefox?

I’m running audio via a Steinberg UR44C and have already fiddled with its settings related to sample rate, buffer size, USB mode, etc.

If this sounds more like a Firefox bug report than a user-mode-solvable issue, I’ll submit one.