A while back I posted a question in this forum (not able to find that thread to link to here) that involved Settings under the Cornerstone option in the admin menu. Settings did not appear under Cornerstone which prevented me from assigning permissions to user types. I spun up a dev instance of my site and did some rocket surgery.
select option_id, option_name from wp_options where option_value like '%cornerstone%'; gave me a list of entries in wp_options that were probably related to my issue. In that list was ppc_admin_menus_order which seemed like a possible culprit for my issue . Deleting that record using delete from wp_options where option_id = row#; in my DEV INSTANCE fixed my issue and allowed me to configure Cornerstone permissions for my users.
Posting as this might help someone else with a similar issue.
*** do not try this in prod - only in a dev instance ***