The fix for JDK-8141492 introduce the changes to the stylesheet.css, which is imported to all out javadoc files:
These lines were added:
=====
a[name]:before, a[name]:target {
    content:"";
    display:block;
    height:120px;
    margin:-120px 0 0;
}
a[id]:before, a[id]:target {
    padding-top:129px;
    margin-top:-129px;
    color:red;
}
=====
This caused an incorrect rendering of some existed javadoc files.
For example check the difference between these two pages:
http://download.java.net/java/jdk9/docs/api/javax/swing/package-summary.html
http://download.java.net/java/jdk9/docs/api/javax/swing/package-summary.html#related

The links above points to the same page, but in the second case the "Related Documentation" paragraph is incorrectly rendered. The reason is that it has an anchor name="related".
The situation became worse if javadoc in this file will use "id" instead if 'name', in this case the text "Related Documentation" will be RED, which is really unexpected.
Note that <a> name attribute is not supported in HTML5 and id attribute used instead.

The fix for this issues also addresses the test failures caused due to fix for JDK-8177562.