I suspect you are using Folder View within the MP USB UI to access your tracks. If so, as
reported a couple weeks back (see the section in that post on Problem Areas: Sort Order), Tesla is no longer using the directory/filename structure alone to sequence tracks within Folder View -- they are intermixing use of some tag data. I agree that's a very poor design choice on Tesla's part, and IMO sort sequence has now become irrational in Folder View for normally-named and tagged media.
POSSIBLE WORKAROUNDS:
1) It may not work for you depending on your file naming and meta tagging, but the simplest thing to first try is access your same tracks via Album View (not Folder View). For me using my former & present file naming/tagging workaround process, Album View sorts correctly by ALBUM tag, then uses the TRACKNUMBER tag for playback -- albeit Tesla still does not handle multi-disc albums using DISCNUMBER as it should so that will likely remain a problem for the example you provided.
2) If Album View does not work for you, IMHO you're basically stuck unless you want to try renaming/tagging your tracks and live with some UI anomalies. IOW, I think what you'd want to try is:
- Keep all of the tracks for the same album or audiobook in a unique named folder on your USB device. Ensure each of those related tracks has the same ALBUM tag.
- Then, add a unique sequence number in front of TRACKTITLE (that's the meta tag, not filename) for each track within each album. Be sure to keep those sequence numbers unique across discs in any multi-disc albums to ensure proper sequencing of multi-disc albums. E.g. "01 First Track of 1st Disc", "02 Second Track of 1st Disc", "03 First Track of 2nd Disc", etc.)
- Then give Folder View another try. No promises, but from what I remember from my testing nearly 3 weeks ago, that may work. The new issue these changes will cause is going to be the track titles appearing across the UI will have those unique sequence numbers in front of them. Annoying perhaps, but proper playback sequence may be resolved assuming that's what's most important to you.
Good luck!