Since the upgrade to 10.0.2, no sound appears to be playing via HDMI anymore at all, neither video soundtracks, nor music files, nor system sounds. I haven't noticed any difficulties with video playback yet, though (thus different from this issue). After Switching back to 10.0.1, everything works again.
I am attaching the debug log I got when trying to play one of my flac files. If anything else is needed, I'm glad if I can help.
And, since this is my first post here: Thanks for your amazing work!