I just spent about a half hour searching the forums, but I can miss things so pardon me if I have.
Windows 10 64 bit, portable MB 3.3.7071, FiiO X5 Gen III running a custom fork of Android 5.1.1 (kernel 3.0.101+). All syncing performed using mass storage mode over USB 2.0.
I noticed that my synced playlists were showing tracks out of order on my device. I checked the playlists' track orders by opening the m3u8 file on the device using Notepad. The tracks were out of order compared to the playlists in MB on most of the playlists, only in order on very short playlists consisting of one or two albums.
My playlists are for specific artists and include tracks from multiple albums by that artist. I sort them by the original year, then the album, then the track number and then I use Update Play Order to set the absolute numbering in MB. The ordering issue appears to be a random re-ordering of albums. The tracks within the affected albums are in order, but the whole album is moved to a different spot on the playlist. An album that should be at the end of the playlist might appear at the beginning or in the middle (for example, no pattern appears to be present, multiple albums affected per playlist). When I check the mbp files on my desktop using Notepad, the order of the tracks is correct, so the issue only appears on the synced lists on the device.
So, I spent a couple of weeks playing around, and I have a consistent problem I can reproduce:
1) I set up a folder on my desktop and make it a virtual device. I use identical settings as I do with my X5 with the following exceptions:
-I am not syncing all music.
-I am only syncing one playlist.
2) I create a new playlist in MB, manually copy the tracks from the test playlist into it (Ctrl+a, drag and drop). I then delete the original test playlist and rename the new playlist to the same name the original had.
3) I sync the virtual device. The play order is preserved as it should be in the m3u8 playlist in the virtual device. It's a perfect match to the absolute order in the mbp file and as displayed in MB.
4) I sync the X5. The playlist files sync to the device as usual overwriting the existing files on the X5. The test playlist synced to the X5 has the issue. A re-check of the mbp file on my computer shows that it still has the correct ordering.
5) I sync the virtual device again, the only file transferred is the test playlist, overwriting the existing file. Opening the test playlist that resides in the virtual device folder using Notepad shows that the play order is now incorrect, identical to the incorrect order on the X5.
I can repeat these steps ad nauseum, and always get the same results.
Here are my sync settings (checkboxes and fields are left blank if not noted):
-delete tracks and confirm deletion are both checked
-The storage path is the drive letter of the SD card on my X5 and the folder path for my virtual device
-I am using a naming template:
Music\<Album Artist>\<Original Year>-<Year (yyyy)> $Left(<Album>,20)\<Disc-Track#> - $Left(<Title>,20)
-the other naming templates are not used and are left at their default values
-split cuesheet files is checked
-playlist path:
-playlist save as format is M3U8
-copy to folder.jpg is selected, resizing to 500
-always copy to lrc file is selected
I know there is at least one other X5 III user on the forums, but the issue is clearly happening on the MB side given that the issue affects the virtual device only after syncing with the X5. It confuses me that the mbp file has the correct ordering and yet the problem persists until I delete and replace the playlist with one of the same name.