Javadoc navibar's tab "tree" doesn't point to package-tree.html but point to overview-tree.html

I’m using gradle build to generate javadoc files. And for the navigation bar in the top, I click the “Tree” tab. It should point to package-tree.html but it point to overview-tree.html.

Could someone tell me why and how to fix it? I have no idea since it just generate automatically and I did nothing special.

My tab:

Skip navigation links

The right one:

Skip navigation links

Thanks.