My 08 KK doesn't seem to have this problem. It blows air where it's supposed to, according to the dial. Of course, I have the manual control. Does yours have the automatic climate control feature, where you select a temp you want, and let the system maintain it on its own? If so, that could be part of your problem.
The gripe I have with the fan is that it makes a heck of a lot of noise, and hardly blows any air. The Explorer I used to have made about as much (maybe slightly less) noise on the high setting, and had a LOT more powerful air flow out the vents than what this Jeep is capable of. It reminds me of those crappy plastic floor fans from Walmart that makes lots of noise and barely move any air at all. If somebody knows of a fix (even an aftermarket upgrade) for this, I'd be interested, but I'm not holding my breath.