Reactor builds fail when multiple modules with same groupId:artifactId, but different versions

In versions 3.1.0 through 3.6.2, when a reactor build has multiple projects with the same groupId and artifactId, even when different versions, the javadoc fails with:

Exit code: 1 - error: module not found: com.aoindustries.example

Plugin 3.0.1 works.

We have created a minimal example project that demonstrates this bug:

https://github.com/aoindustries/maven-javadoc-plugin-failing-multiple-projects-same-name

— Copy from demo project README.md —

To Reproduce:

1. Clone this project: git clone https://github.com/aoindustries/maven-javadoc-plugin-failing-multiple-projects-same-name.git
2. Change to project directory: cd maven-javadoc-plugin-failing-multiple-projects-same-name
3. Perform build to see error in jar goal: mvn verify
4. Also fails with javadoc goal: mvn clean compile javadoc:javadoc

Notes:

• Can build individual modules directly, such as (cd module-1 && mvn verify)
• Reverting to maven-javadoc-plugin version 3.0.1 makes it work
• Changing the groupId or artifactId in either module-1 or module-2 makes it work.
• Changing module names, package names, or class names in modules has no effect.
• We believe this to be distinct from Issue #673