When configuring SCIM provisioning, in Azure AD/Entra you may want to include the sAMAccountName of the user but it is not available as standard from the field selection but can be added with the following steps:

1. Modify ADConnect configuration to include SamAccountName (under Azure AD Connect app -> Customize synchronization options -> enable Directory extension attribute sync -> Directory Extensions -> add sAMAccountName)
2. Do a full sync
3. Create Enterprise App
4. Under Provisioning -> Mapping change user sync setting
5. Add mapping for new field (should be name extension_xxx_sAMAccountName) to whatever SAS app field you want it to populate

Use Provision on Demand to test.