4th gen has stopped playing all songs in order. How do I fix this?

It is still generally following the alphabet but it skips dozens of tracks. An artist from A, then C, then a couple from L, then M, etc.

Nothing was changed before the problem first occurred. Since then, I've verified all tracks are still on the player, erased them all, resynced to put them all back on, played them from itunes, unplugged and plugged back in to make sure they all still show up...and through every step it still skips most tracks.