Open the wiper shroud under the bonnet.
Undo the removable clips on the right side where the cabin intake is.
Lift the shroud and see if something is obstructing the door which is either behind a mesh cover or a cabin air filter.
Good chance to either replace the cabin filter or put one in if there isn't one.
If that is all fine, I would suggest the actuator is on its way out.
Remove the glove box and the instrument pad side trims. Get a light up under there.
The actuator is up high on the left. Green wiring connector.
Use a stubby (As short as possible) phillips head. Two screws holding the actuator onto the housing.
Replace actuator.
Recalibrate.