Thats strange. Try running the # plesk bin admin --disable-access-domain command over SSH. Does change the {{ get_password_link }} link to the server hostname?
The # plesk bin admin --disable-access-domain command sets the control panel to be accessed on port 8443. Looking at the output from the SQL query you posted your control panel URL already contains the 8443 port (pl1.<domain>.<tld>:8443). So it should not change much for you. However my hope is that, somehow, it does change the {{ get_password_link }} url for you. No guarantees. But it's worth a shot I think and should not break anything.
If I am not mistaken the password reset email template also uses the {{ get_password_link }} tag. So you could do a "forgot my password" for testing purposes. No need to create another customer I think.
If you're not feeling comfortable changing or testing things on your server you can always contact Plesk support to have them investigate the issue.
that link already used the hostname. So created a new user, set it to self-activate. Good news and bad news.
The good news: something changed and {{ get_password_link }} is now properly filled in.
The bad news: {{ hostname }} still gets filled in, but is no longer a hotlink like it was before