First off, I would only get one of the HX, and sometimes I have noticed that companies bs their RMA's. They add something or make a minor modification to make it work then send it back. I don't think Newegg would do this, but 2 times in a row is a bit much. I have seen motherboards need multiple RMA's, but that was due to DOA's and shipping damage.
Sorry for some strange posts, that is what happens when I first wake up or stay up to late.