When using AAD Sign-in functionality profile for MPOS, the authentication defaults to "Windows Security" pop-up if the MPOS PC is joined to a domain and the organization uses AZ as well as Active Directory. Please implement Azure AD Forms based authentication within MPOS so complete authentication experience can be handled by the application instead of handing off to the OS. The hand off can cause an issue when organization has policies defined that for example restrict username/password sign-in and enforce PIV only sign in.