[O] Bug: org-list-demote-modify-bullet doesn't work with alpha characters to unordered list [9.1.14 (9.1.14-1-g4931fc-elpaplus @ /Users/bigtyme/Programs/scimax/elpa/org-plus-contrib-20180917/)]

[Jeffrey Spencer]

Remember to cover the basics, that is, what you expected to happen and
what in fact did happen.  You don't know how to make a good report?  See

    https://orgmode.org/manual/Feedback.html#Feedback

Your bug report will be posted to the Org mailing list.
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The first two work below but going from alphabetical to unordered list
(second two)
doesn't work. Is there a reason or way to fix this?

(setq org-list-demote-modify-bullet
     '(("1." . "+") ("A." . "a.") ("a." . "+") ("A)" . "+")))


Emacs  : GNU Emacs 26.1 (build 1, x86_64-apple-darwin15.6.0, NS appkit-1404.47 Version 10.11.6 (Build 15G20015))
of 2018-06-03
Package: Org mode version 9.1.14 (9.1.14-1-g4931fc-elpaplus @ /Users/bigtyme/Programs/scimax/elpa/org-plus-contrib-20180917/)