I have a Saturn Outlook, but I'm one of the guys who has had problems and been posting on the Acadia site. Since they are the same vehicle, one of the reasons there is so much more on this on the Acadia site is that there are 5 times more members on that site, so a much larger sampling. (Almost 2300 on the Acadia forum, only 400 on the Saturn and almost 800 members on this site)
But for sure, it is a "real" problem and one that many of the dealers seem to be having a hard time troubleshooting. It is a complex issue. I also have a 2005 Corvette that was one of the first cars to use the new version of the GM OBDII computer systems and I went through many of the same issues with it. An after market Battery Saver was the solution for that car. GM was pretty much no help at all. I almost can't believe I bought another GM vehicle and now I'm going through the same things again....and this ain't no Corvette!