Default script installer won't accept server template

Under Server Templates > Default Settings > Default Script Installers

In the database name field, I use {DOM}_wp, to install WordPress on Virtual Server creation. This has worked for awhile without issues.

I just noticed that my configuration was changed to Main database. Now when I try to set it to {DOM}_wp,

I get an error:

Failed to save server template : Database name in row 1 does not contain any substitions (like ${DB})

I am attaching the screen capture.