I’m sorry I missed what you were trying to describe, though I’m not sure I did as you can see in the screenshots below. First, here is an example of how I have my folder for a multi-CD set with the booklet only in the first CD. It appears to be essentially the same as your example (unless I’m missing another key feature which if you can detect, I would be most appreciative):
Next are the results of this structure within Audirvana, just as you have shown, though as you’ll see, the PDF does not show up even though I have assigned the exact same album title to every CD:
I assume you do have unique track titles for each track and only the album title is the same?
Finally, how I got my multi-CD set to work is by placing every track from the previously separate folders into one single folder along with the booklet PDF, as shown here:
As I said earlier, why your way works for you and why my way works for me is a mystery unless we can identify another difference I’m somehow missing. At least I have it working, though my way is certainly less organized than yours–I just I wish I could get your method to work. I’ve tried it in both A+ and the latest version of Audirvana.