What triggers an audiobook showing up in the menu?

I’ve tagged and loaded 15 audiobooks on this Jam, and only the first 11 are showing up. I see the folders & files in the Audiobooks folder on the Jam, but when the media is refreshed, they simply aren’t there.

What could I possibly be doing wrong?

[More Detailed]
The folders look like this:

01 - BookTitle1
02 - BookTitle2
03 - BookTitle3
04 - BookTitle4
05 - BookTitle5
06A - BookTitle6 (99 files)
06B - BookTitle6 (99 more files)
06C - BookTitle6 (98 files)
07A - BookTitle7
07B - BookTitle7
07C - BookTitle7
08A - BookTitle8
08B - BookTitle8
08C - BookTitle8
09 - BookTitle9
10 - BookTitle10
11 - BookTitle11
12 - BookTitle12
13 - BookTitle13
14 - BookTitle14
15 - BookTitle15

The Jam is slightly more than half-full.

I installed these books 1 - 5 and 9-15 and then back filled with the larger books 6 -8.

What I see in the Audiobooks menu is 1-5, 9-15, and just the first two of book 6, so 6A and 6B. If I remove ALL books and copy over just book 6 or book 7 or book 8, they show up fine and play as expected. So, what could be causing some books to list in the menu and others to not do so?

Hi @DJGray,

Have you opened a Support Case? If not opened, for more information, please contact the SD Technical Support team for the best assistance and troubleshooting:
https://kb.sandisk.com/app/ask