Had a chat with Support, the issue where addon domains are still pointing to the main domain is not fixed yet, they said they are working on it.
Something strange -- changes of the webcontent done in CPanel do not affect what content is served, i.e. I change a html file with Cpanel, but it never gets updated when accessing it with a browser. Maybe they changed the CPanel server and I am changing things on the old server? I tried domain.tld:2083, that should be the correct CPanel server, but it goes to the the same one as before.