I’ve just rolled out version 6.0.27 of the virtualmin-config package. This package only impacts new installs (or later runs of the virtualmin config-system command). It has a few fixes for CentOS 8, and a couple of minor bugfixes (PEM cert for ProFTPd on fresh install and compatibility with older clients via NoSessionReuseRequired, some minor config tweaks).
I am reverting the Debian/Ubuntu repos to the previous package, which may or may not fix the problem…but, worth a shot while I try to figure it out.
You may need to apt-get clean and install.sh --uninstall (but, don’t ever run --uninstall on a production system or one with anything you don’t want to lose, as it is very destructive) before re-running install.sh.
It doesn’t matter. It is normally only used during Virtualmin installation. (It can be used later when adding services that weren’t enabled during installation, such as adding mail processing tools to a system that was originally installed with --minimal).