Thank you for posting this in Microsoft Q&A.
I understand that Azure SAML is not sending one of the configured group claim attributes in the SAML response for a user, although all other users are able to receive group claims.
It appears to be an issue with one user, not the Azure SAML. To better understand the problem, could you please share more details about the configuration of group claims? For instance, which group option have you configured in the SSO configuration? Also, could you please verify whether the user exists in the group that you have configured in SSO?
Thanks,
Navya