We have a 2016 Greyhawk 29MV. We go to a lot of festivals and so we use the generator a LOT (already have 350 hours on it). We have had the CO alarm go off many times for us. It really is annoying, as it usually happens between 4-5am (never in the afternoon).
I do have a Gen-Turi extension that I use, but it will still go off. Now, what i have found, is that if I set the fan on the A/C to "ON" instead of Auto, so that it continually recirculates the air, it doesn't happen. This is great for the warm summer months, but when we use the RV this fall, where we have it set to Heat, then the fan function isn't available. Not sure how that will work out.
When the CO alarm does go off, we sometimes smell gas. We shut down the generator, and open the door and let it air out for a while. Then we can start it back up. Again, in the cold months, this is a pain. I have already had the dealer replace the CO2 alarm, but it didn't fix anything. Not sure if there are any other work arounds.