Frappe v13 system notification: Adding email id in 'Receiver By Document Field' is not working

In frappe v13 notifications, I am trying to send system notification by adding email id in ‘Receiver By Document Field’ field of ‘Recipients’, but it is not sending system notification to that user.

Can anyone please let me know how to use email id in recipient field of Notifications doctype?

We are also looking for this functionality - does anybody have any ideas?

edit: looking at the code [1] it doesn’t appear to be possible at the moment

[1] https://github.com/frappe/frappe/blob/develop/frappe/email/doctype/notification/notification.js#L62-L91