Ok, so I used mp3tag to create a playlist with several of the songs on my usb and it worked fine.
The only setting change I did in mp3tag was disable the APE tags:
Not sure if that would make any difference.
Had the ID3v2 set to UTF-16, not sure if ISO-8859-1 would make any difference.
I wonder if it is an issue with directories or formatting. Like Nklem, I just let it play thru the specified directory. When it warms back up I will test m3u file formats to see what it does. Hope it isn't a bug in SYNC.
MAK Stockholm 20x8.5 with KUMHO ECSTA 245/45/ZR20
https://www.macheforum.com/site/showcase/2021-mach-e4x-premium-color-rapid-red-interior-light-space-gray.81/