We have found that the database clash check when creating virtual server do not work properly checking all the databases. Probably It checks only the automatically created databases on virtual server creation. But did not check the additional databases created in them.
How to reproduce:
Create 2 virtual servers: onedomain.com seconddomain.com
then for seconddomain.com in virtualmin go to Edit Databases> create database and fill the name as for example "blog".
now try to create sub-server in onedomain.com with domain blog.onedomain.com. It will fail with the message:
Failed to create virtual server : A MySQL database named blog is already owned by virtual server seconddomain.com
But is should not. It should add
In all other cases we have used the database clash check works and add suffix to the name.