unpack behaves differently in multi-module build

During a multi-module build where one project unpacks the war from an earlier project (example attached), performing a "mvn clean test" fails with
"MojoExecutionException: Artifact has not been packaged yet. When used on reactor artifact, unpack should be executed after packaging: see MDEP-98."
at AbstractDependencyMojo.unpack(AbstractDependencyMojo.java:229)

#This will pass
mvn clean install
mvn test

1. This will fail
   mvn clean
   mvn test
2. although the custom-portal project failed, it passes when run by itself
   cd custom-portal
   mvn test