Apple Music for Windows plays to a disconnected speaker
This is probably related to the issue others have mentioned about the inability of Apple Music for Windows to switch output devices. I have new speakers that have a "power off when idle" feature. If I come back to my PC after this has happened and power the speaker back on, Apple Music will not output sound anywhere, including the speaker it was using before, unless I restart the application.
Massively frustrating. Every other player I've used on PC going all the way back to Winamp twenty years ago did this correctly.