changeSet contexts created with maven generateChangeLog are in parentheses

I'm using Liquibase to generate a changeLog from an existing database via maven generateChangeLog goal. I've added changeSetContext to the plugin configuration with the value "new". Looking at the generated changeSets, the context is set to "(new)".

When I try to update the database via maven update specifying "new" as contexts parameter, the changesets aren't executed. After I removed the parenthesis from the generated changelog manually, the update worked as expected.

AFAIK boolean expressions are allowed within the context parameter, so maybe the maven plugin isn't capable of parsing it?