My wife's bike is having this exact same issue.
We purchased two 2017 SESG's on April 1st and I rode her's for the first time yesterday. Mine is not suffering from this issue, but on her's the throttle sticks a little at the very first 5 or 6 mm's and doesn't return completely sometimes.
I believe what you'all are describing is the same issue as in, the throttle is probably not completely closed sometimes when it is shut down. Her's idles about 100 or 150 rpm lower than mine too. I did stall it once and fortunately it was upright at the time. Two other times I almost stalled it going around a corner at an intersection and one of those times came very close to dropping it. You have to be ready to apply a good amount of throttle when this happens.
Never had a problem like this for the last five years riding our 2011 Limited's so this one definitely needs to go in and have the throttle checked.