On two separate sites I have the plugin installed. Same WP version and same plugin version. On one (and actually also on another that I have) the secondary title appears on the main posts page - in the admin area - where all the posts are listed. I see the secondary title AND the main title. This is super useful because the way I'm using it I have the main title showing in one place and the secondary one in another. It's nice to see at a glance which ones are done and what I've called them. For some reason on this one site I only see the primary title. The secondary title just doesn't show up there.
Any ideas? I can't figure out what could be causing this difference.