mvn help:describe returns a different version than mvn help:effective-pom returns:
However, when I run mvn help:effective-pom
My pom structure is quite simple: just a parent pom.xml with the pluginmanagement section as above and a child pom using that. I have tested with both maven 2.0.8 and 2.0.9.
See the discussion here: http://www.nabble.com/Wrong-output-of-mvn-help%3Adescribe--td19168212.html