Valid properties which look self referential fail to resolve

In 2.0.9 properties which look self referential but would otherwise resolve to a system property are failing due to fixes for MNG-2339. Current example is any version of jruby shared pom at
http://repo1.maven.org/maven2/org/jruby/shared/1.0.1/shared-1.0.1.pom

which contains:
<java.specification.version>$

</java.specification.version>

The question is whether this should be valid or not, but it has worked in every version up to and including 2.0.8 because System properties were available in the first interpolate step. In 2.0.9 this first pass does not include the system props and an exception is thrown because of the self reference check.