Digital Signature tag (:digsig) behaves like e-sign in browser when using Adobe Sign API

I am using Adobe Sign REST APIs (tested via Postman) to send agreements via email.

Environment:

• Acrobat Pro subscription

• Agreement created using Adobe Sign API

• PDF contains a Digital Signature text tag (:digsig)

• Sending Group has Cloud Signatures and Download & Sign with Acrobat enabled

Observed behavior:
When the recipient opens the agreement in a browser, the Digital Signature field is rendered as a simple e-sign input box, allowing typed or drawn input instead of a certificate-based digital signature.

If an e-signature tag (:signature) is used, the signing flow works as expected.

This issue is consistently reproducible when using my account, while the same API flow works in Adobe’s Postman demo environment.