Possible problem with @aggregator and forked lifecycles

In the Clover plugin the report mojo is an aggregator (http://svn.apache.org/repos/asf/maven/plugins/trunk/maven-clover-plugin/src/main/java/org/apache/maven/plugin/clover/CloverReportMojo.java). It also spawns a forked lifecycle:

* @execute phase="test" lifecycle="clover"
* @aggregator

When I run this clover report on the Cargo API module, which contains children modules, all the modules are executed several times as shown in the attached logs. They should be executed only once. The @aggregator is supposed to execute only once and it executes several times.