Thanks for the reply.
Yes. If I shuffle a collection of folders with, say, 500 tracks, it says 1/500. I play through a few and it shuffles fine, then when I add current track to playlist using the menu button on the album art in the Now Playing screen, it resets to 1/however many tracks are in the current folder.
Is there a way to disable this, so that it carries on shuffling through the original 500 (in my example above)?