When execute mvn release, using the maven-release-plugin with the version 2.3.X or 2.4.X, it succeed but the package is snapshot version but isn't a valid release one. it is because the version. It works fine for me that update the version of maven-release-plugin to 2.5.X.
The the https://issues.apache.org/jira/browse/MRELEASE-812 as a reference.