build failure when running "package assembly:single" on a project

Following a question opened on stackoverflow (see here http://stackoverflow.com/questions/29199748/maven-assembly-plugin-do-not-trigger-search-of-default-assembly-descriptor) concerning a build failure with the maven-assembly-plugin, I could isolate the test-case that makes the issue appear.

Test Case :

• configure a project with a simple assembly, the property skipAssembly appears nowhere
• run the tasks "clean package assembly:single"

Current Result :
Build Failure

Expected Result :
Build Successfull as when running "clean package"

Workaround :
Add the property skipAssembly to true in the plugin configuration and add the property skipAssembly to false in the configuration of the execution

I have a project in my workspace that I can attach once the ticket created if I have the authorization to do so.