I have a similar problem on my 2012 SCrew wtih ~20k miles. I get almost no heat out of the drivers side foot vents but a whole lot out of the passenger side. It also has a whole lot of flow out of the face vents, which should be no flow when on foot only. The only work around I have found is to put it in dual-climate mode, then it all seems to work right.
Calling the dealer today.
Calling the dealer today.