mvn dependency:tree ends up in a nullpointer

[Vach, Matthias]

Hi all,
I need to define that any versions of javax.el:el-api are provided by my 
runtime system and must not be packed into my ear.
To avoid excluding that artifact javax.el:el-api from each and every dependency 
where it is referenced, I defined it as explicit provided artefact:

<dependency>
  <groupId>javax.el</groupId>
  <artifactId>el-api</artifactId>
  <version>[1.0,)</version>
  <scope>provided</scope>
</dependency>

This is building fine and works as expected but
Sadly the version definition [1.0,) leads to an null pointer:

[ERROR] FATAL ERROR
[INFO] ------------------------------------------------------------------------
[INFO] version was null for javax.el:el-api
[INFO] ------------------------------------------------------------------------
[INFO] Trace
java.lang.NullPointerException: version was null for javax.el:el-api
        at 
org.apache.maven.artifact.DefaultArtifact.getBaseVersion(DefaultArtifact.java:390)
        at 
org.apache.maven.artifact.DefaultArtifact.getId(DefaultArtifact.java:225)


Can you give me the reason for that NPE?

THX for your help,
Regards Matthias