Trouble when deleting server alias

Hi there,

I have 2 freshly installed Virtualmin servers running Ubuntu LTS 18.04 having the same Problem when deleting website aliases.

I get this error message and afterwards I cannot recreate that specific alias without going into the /etc/sites-available and manualy deleting the alias from there.

The error is always the same (line 3216).

Here the copy/paste:
Deleting mail aliases …
… done
Removing from target virtual website …
… Apache website failed! : Unescaped left brace in regex is illegal here in regex; marked by <-- HERE in m/^%{ <-- HERE HTTP_HOST}\s+=(webmail|admin) at /usr/share/webmin/virtual-server/ line 3216.

Deleting server details for …
… done

I think this is a BUG because on my older servers (Ubuntu 16.04) I do not have this issue.