If you are using the Special Menu Items module to add things like HRs and unlinked titles to your menus, you might run into the Breadcrumb issue.

If you have a non-linked menu item it may show up on your breadcrumbs as a plain text title which you may not want to see. There are a number of issues for this in the modules queue, but as far as I can tell it has not been fixed.

My quick fix is a function in template.php