Make sure your hubs do not have identical capsules in them. For instance, let's say you have three articles, one about corn, one about apple pie, and the other about ginger root. They are all different and original, but in each one you have a, "About: Xanzacow section" and it is exactly the same on each hub.
This is bad.
You could be flagged for duplicate content and the publication will be blocked. This may not be the issue, but it's worth checking.