I agree, this has to be the STUPIDEST feature ever..My 2017 Jaguar has it and by reading some forums, I was able to find the control module for it and un-plugged it to disable it..
First of all; I think it is unsafe..as if you have to take off fast to avoid being hit by another car out of control or whatever..that 1 or 2 seconds it takes to restart and go could mean the difference between life and death.
Next:..the wear and tear on the starter motor and battery can't be good either.
All this to save maybe 1 or 2 miles per gallon...Big flippin' deal!
I would get with a GMC technician at your dealer (Not the Service Advisor) and find out where it is, or maybe a software change can disable it.
BTW..Like you, I always encourage EVERYONE signing up here, to put their Location and/or Country/State..(No addresses needed), but this way folks in YOUR area may have a better handle on your unique problems and issues and advise you of a BETTER dealership, if one exists in your area.
But go to your PROFILE under "User CP" and add YOUR lOCATION..IT WILL SHOW UP UNDER YOUR USERNAME/AVATAR.