Classpath is setup incorrectly if assembly-plugin is used several times on the same reactor

I have some projects (which use the maven-assembly-plugin) sharing the same assembly-descriptor. Thus I setup my projects as described in http://maven.apache.org/plugins/maven-assembly-plugin/examples/sharing-descriptors.html. In principle that works fine.

Unfortunately when invoking maven on a higher directory level (that means putting more projects in the same reactor) I got Classpath related assembly-descriptor-not-found problems in my new projects. This problem occurs whenever at least one of the other projects also use the maven-assembly-plugin. These other projects typically do not have the dependency specification for the shard-assembly-descriptor project. Obviously in that case the shared-assembly-descriptor jar is not put on the CLASSPATH when the plugin is invoked for my new projects.

Note that there is a workaround: When adding the dependency to the shared-assembly-descriptor project to all other projects using the maven-assembly-plugin, everything compiles perfectly. However, this workaround is a bad one.