If anyone else is having this problem, I think I solved it myself: it looks like copying and pasting rows gives each object the same name, which creates a duplicate in the Preview PDF View. If you make different names for each copied object in the hierarchy view, you shouldn't have this problem.

Hi. I have created a table in a dynamic form in Livecycle. The table appears exactly how I want it in the design view, but when I preview the PDF, there is an extra row that's messing up the rest of the document. Published versions have the same extra row. I can't find the extra row in the hierarcy ...

I'm not sure if anyone is still reading this post, but I found out that the form needs to be saved as Acrobat 8 (Dynamic) XML in order for the dynamic features to work.