core_user_create_users does not validate custom fields

Hello, I've searched the forum and don't see this question anywhere.  If there is already an answer please feel free to direct me to the discussion.  Apologies if this is a duplicate.

When sending a request to the core_users_create_users endpoint custom field data is not validated in accordance with user profile fields settings

I've created a profile field (text) which is set to be unique.  When trying to enter a non-unique value through the Moodle User Admin UI this rule is enforced.  When sending the create user request to core_user_create_users accounts are created with the same text in the field that should be unique by definition.

In reviewing user/externallib.php:create_users function (lines 250-257, Moodle 3.7) it appears that there is no call to validate custom fields based on the rules for the field as defined.

Thanks for your help.
Brian