[stumped]

Latest cc version. About says 5.2.5.2.(539)
Seven books on device. Grouping by author confirms that my author surname groups are
one a
two c
three h
one l
to the right, where I set display to a z by author, I expect an a z ordering of cover thumbnails
But That thumbnail list places the l between two of the h and it places ho before ha.
So I get this order Corey, hobb, lallo , harari, helton

All other sorts e.g. by title seem well behaved.
I have tried added, removed some of the books and exited restarted cc. The sort order is consistently wrong. The same wrong order is applied if I ask to see the seven books on a shelf.
I prefer to e-mail screen shots rather than type full author names. Is there a known bug. Is a z a full sort or only first letter. I.e.should ha precede ho or is that random.