The current implementation of the 'add-features-to-repo' goal in the features-maven-plugin allows you to list feature descriptors and names of features you want to copy. If you have multiple versions of the same feature (e.g. if you accidentally pick up another version of the same features descriptor through a <repository/> element somewhere in one of the feature descriptors), the plugin just pick one of the two feature version and the only way to control which one is usually be reordering the feature descriptor configurations.
It would make a nice improvement if you could somehow specify a version for a feature (e.g. <feature>cxf/2.4.3</feature>) in your POM file in this scenario to clearly/reliably pick one specific version if necessary).
Cfr. http://karaf.922171.n3.nabble.com/Features-td3423534.html for some background on this issue