Fix Forum Breadcrumbs
If your bbPress forum page is also your front page, your bbPress forum breadcrumbs may include the forum main page twice. (The first breadcrumb is a link to the site front page, and the second breadcrumb is a link to the forum main page – but these pages both show the main forum archive.)
This plugin removes the second breadcrumb entry.
If a problem with duplicate breadcrumbs persists, your theme may be affecting the bbPress breadcrumb settings; you’ll need to look into that separately, or try a different theme.