When switching the subscription address from Primary(x@y) to just x@y MM3 should not send unsubscription and subscription notifications to the same email address
I create an account dpa-mailman-zz7 at https://lists.mailman3.org/mailman3/lists/ . This account has a single email address attached, which happens to be the primary address.
Over the webinterface - https://lists.mailman3.org/mailman3/lists/mailman-users.mailman3.org/ - I subscribe to the mailing list with the Primary address (my-address@example.org). I receive a Welcome message.
After that I click on “Manage Subscriptions” and as email address select just my-address@example.org. The dropdown menu offers two options: Primary address(my-address@example.org) and my-address@example.org, I select the second option. Then I click on “Update email address for subscription”.
Mailman sends an email message to the old address with subject “You have been unsubscribed from the Mailman-users mailing list”. Then mailman sends an email message to the new address “Welcome to the "Mailman-users" mailing list”.
Since the old address is the same as the new address, my-address@example.org, there shall be no notifications about un-subscription and re-subscription.