Gradle javadoc task no longer reports errors and warnings

My API project no longer reports the Javadoc WARNINGs and ERRORs when running gradle javadoc.

My other JavaFX project is reporting them.

I was content with my API having no Javadoc warnings or errors, but was distraught when I discovered wrong javadoc which should have produced an error and failed the build.

Both projects have same build script configuration regarding javadoc.

task sourcesJar(type: Jar, dependsOn: classes) {
    classifier = 'sources'
    from sourceSets.main.allSource

task javadocJar(type: Jar, dependsOn: javadoc) {
    classifier = 'javadoc'
    from javadoc.destinationDir

artifacts {
    archives jar
    archives sourcesJar
    archives javadocJar

Gradle 4.10
Java 1.8

Would appreciate if anyone have insight of what the problem might be with this one project.
Why isn’t javadoc task reporting warnings and errors?

I had to turn on Javadoc validation in Eclipse to make sure.
Edit: It caused so much errors on my other legacy applications that I had to turn it off again.

I have discovered the reason why Javadoc did not report warnings and errors on certain classes.

Javadoc does not run on package private classes (no access modifier).

Even though I have Javadoc in a package private class, it will be omitted from Javadoc, thus it will not report any warnings or errors.