Hi Justin,
Probably approach will be to add the prompt=login parameter, add a prompt=login query string parameter to the AAD authorization endpoint URL. This will skip the SSO and force a login with AAD and also please check this article for the auth code flow - dn645542(v=azure.100)
Hope this helps.
JS
==
Please Accept the answer if the information helped you. This will help us and others in the community as well.