repro.sh

export JAVA_HOME=/Library/Java/JavaVirtualMachines/jdk1.8.0_161.jdk/Contents/Home
export PATH=${JAVA_HOME}/bin:${PATH}
cd /tmp
git clone https://github.com/nasa-pds-engineering-node/exemplar.git
cd exemplar
git checkout 4844ed8f4eeb1c30646e8662bbc91ad7d2683750
egrep maven-javadoc-plugin pom.xml
# Note: no javadoc plugin
mvn install
ls target/*.jar
# You get 1 jar
git switch -
egrep maven-javadoc-plugin pom.xml
# I have added the javadoc plugin which should've been inherited from parent
mvn clean install
ls target/*.jar
# You get 2 jars