Wow! You just answered those questions while I was asking them! So my Edic has a heater that heats up to 210 degrees. No way to dial it down Robert. Its either on or off. What so you recommend?
Too much water left in the carpet can cause a separation of the adhesive, really hot water adds to the problem. A super high PH prespray that doesn't get rinsed out all the way can further increase the chances of this problem. All that said, I've cleaned with a portable using a single 3 stage vac at 300psi, 210 degrees, and a prespray spiked with groutmaster and degreaser and peroxide (thats a pretty high PH) and had no problems.
So be careful not to over wet, make plenty of dry passes, and follow up with the bonnet. You should be fine. Like I said, it's not often that that happens to carpet.
Edit: If you are using a very high PH prespray, you should be using an acid rinse to help neutralize the prespray to prevent rapid resoiling of the carpet.