It will be covered by the Ford powertrain warranty, if they will in fact admit there is even a problem with the transmission to begin with. They are going to listen to your explanation of what you think is the issue, take it for a test drive, and report back that they didn't find anything abnormal. They'll show you a slip of paper from Ford saying that a slight shudder from stop to acceleration is normal.
It may in fact be normal if its happening occasionally. Mine did it from time to time when I owned it. If it happens every time you hit the gas then I would think that it is abnormal. Best advice I can give you is to thoroughly read through this thread as well as the "Problems with the 2012 Focus" thread and determine how bad the issue is with your car. Chevy won't have any idea what to do with it as they are completely unfamiliar with Ford's dual-clutch transmission, and Ford is going to act like its normal thing that the car always does.