Audiobook authors not sorting correctly

Am using iTunes 12.2.2.25. I like to have my audiobooks sorted by Author (last, first) and then by the order in which the books were written. I have gone into the sorting tab for each book, listed the Author as First Last and then in the Sort As field Last, First. For titles, the Title is the original title of the book and the Sort As I use the author's last name and then either a number or a word that names the series of the books and then a number.

If I choose "Audiobooks" from the top right in the window, some authors appear out of order. If I choose "Authors" from the top right and then choose All Authors from the list on the left, all of the books appear properly. HOWEVER, the list of authors below that is in the same incorrect order as if I had chosen "Audiobooks" from the top right.

I've tried everything but nothing seems to work. Is it possible that there is a bug (heaven forbid) or perhaps something in an index file? If the latter, does someone know which file it is, if it would be save to delete it so as to force iTunes to rebuild it? Or should I just leave things be?

Thanks in advance for any help.