I've noticed that the purge-local-repository goal does nothing if certain dependencies are present in the dependency tree of the project.
After some attempts I've found some of the dependencies that can show problem.
See attached pom.xml: if I run mvn validate as is, maven purges the local repository and the log4j jar is downloaded from the remote repository.
Removing the comment around the jasperreports dependency and re-running mvn validate gives the following result:
So it seems that something goes wrong while resolving the dependencies for the project if the jasperreports jar is included, resulting in the purge-local-repository to skip the clean of the local repository.
I dont know if this happens only with jasperreports dependency or if it is something more general.