SSO ADFS missing Name ID but has other attibutes

Trying to get SSO Highlevel API working with ADFS Idp. It appears that the Attributes, Given-Name and Surname are getting included in the SAML post but the Name ID keeps coming in blank. Is there something I need to be aware of when configuring this in the AD? The current setup has the LDAP attribute and Outgoing claim type mapped as the below:

E-Mail-Addresses → Email Address *blank.
Given-Name → Given Name *working
Surname → Surname. *working

A transform rule was also included to take the incoming claim type: E-Mail Address and set to the Outgoing claim type: Name ID. - Outgoing name ID format: Email. [x] Pass through all claim values.

Please let me know if I am missing any steps.

Thanks.

As an experiment, add a claim rule that maps the AD UPN to the SAML NameID and remove the existing transform rule for the NameID.
You should receive a non-blank NameID.
Assuming that works, the issue must lie with your mapping or transform rule for the NameID.
You should consult the ADFS documentation regarding these rules to determine what the issue is.