MuteTab (https://chromewebstore.google.com/detail/mutetab/acofndgbcimipbpeoplfjcapdbebbmca), an extension I use to prevent random particularly loud websites from startling me at 2am seems to have trouble actually muting.
Ideally the core functionality of automatically muting websites would actually mute websites. Alas, even manually setting it to mute or unmute through the extension doesn't have any effect.
Version 0.99.130.1-beta (WebKit 621.1.2.111.4)
Sequoia (15)