Looks like any Power BI App shared with the Entire Org is visiable to the External Users once signed up to view the first App. By clikcing on App then Get More Apps they can see all Apps Shared Inte...
rayishome
Resolver I
Resolver II can confirm the domain is not part of the tenant. We created the email to test external use cases. This email received an invite from the b2b process. What's interesting is this email was used previously to share dashboards externally and was given guest access another workspace.