Ok, I see. This problem is not new and doesn’t related to wpForo Update. Maybe your website was cached and you didn’t see that before, now when plugin is updated all caches are deleted on plugin update process. Or maybe you’ve not checked forum a while. This problem comes from theme or from some plugin which adds extra <p>
paragraphs to wpForo breadcrumbs. You should deactivate all plugins delete cache and activate one by one to find the problem maker. After this you will check the theme.
Here is the screen:

In any case this CSS code may help a bit (only last arrow will not be there). Put it in Dashboard > Forums > Settings > Styles > Custom CSS Code textarea and do Ctrl+F5 on front:
#wpforo-wrap .wpf-breadcrumb p{ display:inline-block; margin:0px; padding:0px;}