I called Kitchenaid about a problem similar to the one you describe - the woman said that the height of the bowl might be too high or low.

She said to put a dime in the bottom of the mixer (I placed it along the inner slant of the raised part). Turn on your flat beater and see if the beater just nudges the dime as it goes around. In other words, there should only be a dimes space between the beater and the bottom. Mine requied an adjustment. I guess if it's too high, it prevents the sides from meeting as well.

Good luck,
Deb