I upgraded to MC 31 and also transferred my library from a HDD to a Synology NAS.
I tested one song and it worked great. Then I clicked the top right "X" to close MC and amazingly, the song I was playing was still going.
I looked around to see what was playing the music and there was nothing. How in the world could that happen? This went on for quite some time.
I'm using a Raspberry Pi with Ropieee and DLNA to my DAC
I restarted MC and played a different song and sure enough the previous song stopped and the new one started.
This time, I hit STOP before exiting and all music stopped.
Did I have a visit to the Twilight Zone?