@xcool I've heard back from the team that shuffle will already avoid repeating any tracks.
My simple tests show this to be the case.
Note that this gets reset if you tap any track or modify the playlist though. So perhaps you've noticed repeating because you've been trying to treat it like the Cambridge app and manually select tracks during playback.
My initial thought is that we don't want to randomise the actual list, but you are welcome to email us with a feature request and it will get reviewed by the full team.