itch.io

It's actually an issue in newest version as well (in fact Steam version is 3.0.2 currently so the same as the one on itch). It seems to be a bug with a sound volume actually being either null or 0 (depending on how it was written) and menu not reflecting it properly. All you need to do is change the volume in menu to any other value than it currently shows, which I assume runs events with setting new volume value. That will sort the issue (or at least it should).

If you're still having audio issues, just go to settings and adjust the volume either direction. It's a strange fix, but it worked for me.