I have also seen a new part number 20985421 in the catalog. This is version DB/DB.
Works perfectly and has done so for a month now. NO ISSUES.
I also don't know why GM doesn't just change out the part number all together. I think they are going to do nothing but have more and more complaints and unhappy customers when they go int time and time again to get it fixed only to be told, "sorry...you are stuck with a SH!T PDIM." I'm sorry...but no one and I mean NO ONE should have to put up with that. If you buy something, you expect it to work...not work half assed and then have to live with it.
I know my dealer really well.
They didn't want to warranty my PDIM saying it wasn't for my car. It was the wrong part number. I had to explain over and over and finally my guy, since he is a genuinely nice guy, caved and said he'd get it. Guess what....FIXED.
NO ONE and I mean NO ONE should have to beg ANYONE to get their vehicle and parts fixed PROPERLY under WARRANTY.