I have one album where I initially scanned in the last track to Sonos first, and then later scanned the entire album. The result is that the track order that appears in Sonos is out of order: track 12 appears first, then 1, 2, 3, .... The track field is correct. I've tried deleting the entire album from my library, rescanning Sonos to remove the album, then re-adding the entire album again, but the track order is the same. If I tell Sonos to play the album, it starts with the last track.
Best answer by Stuart_W
Make sure the Album name is EXACTLY the same on all those tracks. Make sure that each of those tracks has the # of tracks (ie 12) filled in. You can make those changes in iTunes