Incoming email handlers in JIRA can't create new users from the create user function

Summary

While configuring a new incoming email handler in JIRA, setting up with the create user function does not create a new ticket or a new user account.

How to reproduce

1. Add a mail server
2. Configure the incoming email handler, mark the option to create new users, turn on the self-sign up on the user management.
3. Send an email to the newly created email server.

Expected Results

A new issue would be created and a new user account would be created with the new user been the reporter of the issue.

Actual Results

None of the above got created.

Workaround

Create the new users manually. Or, use a default reporter in the mail handler, so an internal user will create the issues on behalf of non-Jira users.