How does automatic portal-only user account and ticket creation work from email?

[Ann Ivey]

What is the expected behavior in Customer Service Management when someone without a portal-only account submits a ticket through email to <my space key>@<my domain name>.atlassian.net?

Under customer experience > Customer Access, I have the following option selected:

• Only customers from organizations that have been added
  • I have added one organization Acme with one associated email domain acme.com.

I submitted email to <my space key>@<my domain name>.atlassian.net from two accounts, xxx@acme.com and yyy@globex.com.

The email from xxx@acme.com caused the following:

• A portal-only user account was created as expected
• The potal-only user was automatically added to the Acme organization as expected
• No ticket was created (why?)
• The user was able to set a password and access their portal account as expected

The email from yyy@globex.com caused the following:

• A portal-only user account was created (why?)
• No ticket was created
• The user was not able to set a password or access their portal account

When xxx@acme.com creates a portal-only account before sending email, the email is correctly converted to a ticket.

I have the following options selected in Gear Icon > Jira Apps > Customer Service Management > Customer Access:

• Allow Accounts to be created for customers
• Allow customers to create accounts
• “Allow anyone to view your support websites and send requests without logging in” is not selected

In both cases, there was no feedback to customer support or to the email sender. When a new user submits a email request, how does customer support become aware of it if all email to the support address goes through CSM and no ticket gets created?

What is the expected behavior for automatic creation of portal-only accounts and associated tickets submittted through email?