Hello @RobStauder,
In regards to SAML everything should be working as intended, though when is comes to IWA we do have some restrictions that are based around the iframing of ArcGIS items into a MS hosted iframe which has a different origin compared to our ArcGIS for Teams application. A call to your ArcGIS content will fail when verifying the securities for your content on our end through this login method. When trying to fetch the general items from an organization, the security of them is the most important, and so we can not support it until there is a proper communication between single application iframing between ArcGIS and different hosted domains (MS).
And if possible, check if you can enable CORS in your organization to be able to provide you with cross-domain requests and allow access to your ArcGIS content through these different hosted domains.
Please feel free to reach out to me directly at ssaballett@esri.com and I would be happy to explore the issue some more so we can provide you a better explanation on what can and can not be done.
Thank you,
Sebastian
