Note: If you don’t have an account with unused invitations, you'll need to log in as an admin and go to https://test.archiveofourown.org/users/USERNAME/invitations to grant some.
Log in to an account with unused invitations and which you don't mind deleting
Hi, username! > My Dashboard > Invitations
Choose and invitation and enter an email to send it to
Make note of the invitation token (the keysmash)
Press "Send Invitation"
Hi, username! > My Dashboard > Profile > Delete My Account
Confirm that you want to delete the account
Log in as an admin
Invitations > Invite New Users
In the "Track invitations" section of the form, fill in the "Invitation token" field with the token of the invitation you sent
Under "Sender," it says queue, which we know is a lie.
It should say "Deleted user." (Or "Deleted admin" as appropriate.)
This is just a display issue. The creator_link helper just displays "queue" if invitation.creator is nil, which is what happens in the case of deleted users (or deleted admins). The creator_id and creator_type are still in the database, and from_queue is still false.
Here's an example from staging, after the creating user deleted: