The whole story is the USB stick works pretty well, but occasionally stops randomizing. I just turn off random and turn it back on. It’s my preferred media for its consistency.
SD plays it’s own game... sometimes it works fine (like the USB stick), sometimes it picks a song and sticks with it (even if it’s Selfie by the Chainsmokers)...
The USB and SD each have their own icon but when scrolling through My Media Library with the “Media” button, there is one setting that is a musical note as an icon and I have no idea which media device it’s pulling the song from, so I can only assume it’s using them all, but not sure. (Both the USB and SD have the identical song list because this is somewhat experimental)...