I have yet to fully understand why we don't suffer uplift lofting more than we do...
It is similar to gliding into ridge lift which is extremely common in hang gliding and paragliding.
Think of ridge lift as a river of air, and likewise for a rising thermal column of air.
There isn't much space for such a phenomenon to materialize in the short distance between the surface and the height of a normally flown kite.
That's why I suspect most vertical air currents that affect kites are the result of rotor turbulence, or similar conditions.