Try creating a DB on Azure and then creating an AAD user there, create user [xxxxUser@abc.com] from external provider. In SSMS, if we script that user to create, we get this script: CREATE USER [testUser@abc.com] FROM  EXTERNAL PROVIDER  WITH DEFAULT_SCHEMA=[dbo]
but if using sqlpackage to extract and script, we get this: CREATE USER [xxxxUser@abc.xom]
    WITH SID = 0xXXXXXXXXX123456B78XXXX1234XXX, TYPE = E;

Steps to Reproduce:

1. Try creating a DB on Azure and then creating an AAD user there create user [xxxxUser@abc.com] from external provider.
2. Use sqlpackage to extract and script, I get this: CREATE USER [xxxxUser@abc.com]
       WITH SID = 0xXXXXXXXXX123456B78XXXX1234XXX, TYPE = E;
3. Import the bacpac.

**Did this occur in prior versions? yes

(DacFx/SqlPackage)