Using a page attribute block to display topics according to the current page works well.
I've created a new Topics attribute in "Pages & Themes > Attributes" and selected a sub category instead of the root category. Then I've added a page attribute block to a portfolio page and selected the the just created attribute. Nothing but the blocks title is showing.

That's funny. Selecting the root category gives me a comma separated list of topics and selecting a sub category gives me nothing.

Any ideas what's wrong, or is it a bug?

Thanks and cheers