Onkyo has good customer support and should take care of you. I decided to return mine because college football season is starting and I refuse to be without a receiver I am going to try the new Denon out so I will see if it displays the same issues the Onkyo did. You can setup the Onkyo the old fashioned way and not use Audyssey and it sounds great, just don't enable Auydssey.
To make note, the Onkyo was a really nice receiver and it is unfortunate this bug passed QA. I guess we can take my XT32 graphs with a grain of salt at this point although it didn't do anything strange to the subs, just the mains and surrounds.
Oh and BTW, it cost me $50 to send mine insured back to the place I purchased it from