When you build an ear with Maven, ejb artifacts need to have <type>ejb</type>, so that they are properly sorted into the main directory of the ear.
If you use an ejb artifact as dependency, this works well with <type>ejb</type> but also with no type tag (i.e. implicitly <type>jar</type>).
Now, if our ear contains ejb.jar with <type>ejb</type> and also has ear.jar as transitive dependency without <type>ejb</type>, the dependencyConvergence fails and Maven seems to be confused.
This caused several problems recently because the developers of the individual jars tend to forget about “this type thing” altogether, defining dependencies on ejbs without proper type and the guys who build the ears then stumble over the resulting virtual dependencyConvergence issues.