I have found an issue with ThreeWP Broadcast creating duplicate posts in child sites too.
I’m running 3.3.1 WordPress as a multisite. I have ThreeWP Broadcast 1.11 installed.
I have deactivated all other plug-ins.
If I chose ‘Find Orphans’ for a post from the posts page and select all child posts to create a link, I find that the link is not created. However, if I edit each post individually, check the ‘Link this post to its children’ checkbox and select the child sites to broadcast to, a duplicate post is created in the child site. The original post is not linked but the duplicate post is linked okay.
It’s not an impossible problem to work around – I can just delete the original child post… but it would be nice to know why it’s happening and if it’s possible to fix.
Edit: This only happens when a child post already exists on the child site: e.g. I have site-a.com/hello and site-b.com/hello. If I try to create a link between these two posts, WP will generate site-b.com/hello-2, which is the linked post. However, if I create site-a.com/hello, WP will automatically create site-b.com/hello as expected.