Thanks. I am just an ordinary users like others, focusing on smaller easier to solve issues.
Now that I am looking, both anon-whonix & whonix-workstation-dvm are tagged as anon-vm based on their sls files during the installation. So I assume that even if it was a new AppVM rather Standalone, the same error might have occurred. I have to investigate the policy files to see what is happening there.
p.s.: I hope one of the moderators could spawn this reply and the OP to a new forum thread. So we could easily work on it.