VPN over Tor on Qubes 4.2 not working - Whonix specific

I originally posted the question to the Qubes mailing list but the issue seems like Whonix specific issue now:
Mullvad VPN over Tor on Debian AppVM → MullvadProxy → sys-whonix → sys-firewall → sys-net works like a breeze.

The anon-whonix AppVM → MullvadProxy → sys-whonix → sys-firewall → sys-net chain doesn’t get any connection.

The only difference is the first AppVM. I tried Fedora and Debian AppVMs and those work well, without any issues. The anon-whonix doesn’t.

Code to set up the VPN is the one below.

Any ideas how to solve that?

UDP issue? See: UDP

For connection scheme User → Tor → VPN → Internet you need to configure the VPN to use TCP.

The connection and config files are purely TCP on port 443. It is selected on the mullvad account like that. Sry I didn’t mention that right away.

The Debian and Fedora AppVMs get through User → Tor → VPN → Internet nicely. Only the anon-whonix → Tor → VPN → Internet doesn’t work.