[@johnjamesjacoby Keymaster 9 years, 8 months ago]

If you create a page with the same slug as your forum index, you can use either the [bbp-forum-index] or [bbp-topic-index] shortcode in your page content to output the list you desire.

bbPress won’t complain, and you’ll be able to customize the page title and content if you desire.

It’s not exactly a hidden trick, but it’s what we use here on bbPress.org and seems to work OK. If that approach is creating a broken breadcrumb, that’s definitely a bug.