my 57 vapp had a user create a custom dashboard and shared for admin to review and modify, and the admin user cannot see the dashboard, but other admin level users can. Is that expected or is this an issue?
"admin" is considered as superadmin and does not belong to Administrator group. So when a user from some group is sharing a dashboard with "Administrators" group it does not mean that "admin" will see that.
This is expected behaviour rather than an issue.