None assigned to is_resolved field when parsing dependencies from a Maven POM

I scanned the pom file from https://repo1.maven.org/maven2/com/wordnik/swagger-java-sample-app_2.10/1.3.1/swagger-java-sample-app_2.10-1.3.1.pom and the `is_resolved` field for the dependency `pkg:maven/com.wordnik/swagger-jaxrs_2.10` has a value of null, when there should be a true or false value.