And if you take it to a dealer to get it checked out, I'm sure that won't get you anywhere. :( Or maybe I've just lost faith in dealers. :)
Sorry to hear of your issue.
The "key" to unlocking the door with the handle is putting your hand around/inside the handle. The sensor on top works better for locking. Just a quick touch of the ridged area will lock it. I've had 100% success using this method for the last 8 months of ownership.
Or it points to a more widespread problem with the system.
FWIW, the Sirius reception in my Sync 2 equipped 2015 is better one I had in my 2014 Camaro. I have yet to have it drop out in the spots where the Camaro dropped consistently.