abitdeef is right. Random for "All songs" is working as expected.No you can select all music and shuffle.
But for "Folder" or "Album" or "Genre" or "Artist" play I would expect to play/randomize all songs in selected folder+subfolders or just the album or just the genre or just the artist and then STOP playing.
Instead it plays what you select and then it goes to another folder. And they call it in the settings: "Play through folders", it is not very accurate name or it is doing more than it should
So I tried this, and to my disappointment, the stutter is still there. it does feel like it's a tad more stable, but it didn't solve the issue for me. I have actually done a factory reset to go with the card formatting.
Just for the hell of it, I went to try the read and write speeds for the sd card, and I found an average of 80MB/s read and 60MB/s write speed. So, memory card quality and format seem to be out of the equation.
Sorry to hear that. If you also tried to play songs only from internal storage of M6 with no microSD card inserted then it is out of the equation. But I think someone already tried this and there were glitches as well.