we have a jenkins root job that are maven-module builds, say they contain mod-a, mod-b and mod-c.
We have associated jenkins-jobs job-mod-a, job-mod-b, job-mod-c. These should be considered downstream-jobs for the sub-modules of the root job. Whenever the root job builds one (or more) of the sub-modules, the associated downstream job must be triggered.

Obviously jenkins allows for this kind of configuration, it correctly displays a proper information in the configuration screens.

But the triggering does not work. The downstream jobs are not started at all.

Is this configuration supposed to work? What could be missing?