What causes the air vents in front to give cold air and hot air at the same time on 2003 Hummer H2

When I turn on the engine i notice that on the passenger side air vent hot air. The drivers side blows cold air. When I shut off the engine and wait an hour it sometimes works properly.

Asked by for the 2003 Hummer H2
its the blend door actuator its the same on a cadillac escalade and a hummer h2 i had the same problem