The problem could be on Topaz’ side. I don’t have V2, but some photos edited with 3.1 or 3.2. The Sonys work fine, but the Canons in fact can not be handled by RT (assuming you are speaking of RT).
When I redo them with current 3.6.X everything works fine. So there seems to be some fix on the part of Topaz. Otherwise… DT has no problem with any of the DNGs…
I don’t remember V2 much, but does it have options to embed or apply some kind of profiles to the DNG? Have you tried various possible settings?