@Jim Johnson ...
First, congrats on solving! Wow!
Don't mean to 'burst bubbles', but sounds like there is a serious
problem concerning quiz bank.
Suggest picking a non-prime time to run the Health Tool.
https://yoursite/admin/tool/health/
The above URL will run the tool without any prompt or option ... that's why non-prime time suggested. Have no idea as to how intensive it might be.
It's not found in admin menus and it is not officially supported but it might provide some clues as well as SQL query fixes to quiz bank issues. I too have seen quiz bank issues (not yours specifically) and the suggested fixes (DB queries run on DB for moodle) did resolve some issues. Enough to fix some courses.
Good luck!
'SoS', Ken