[SwissXC90]

The movement looks normal

Taking my 2009 XC90 as a reference, here is the data from VIDA

Swirl throttle
The swirl throttle consists of a DC motor (12 V), position sensor (Hall sensor) and throttle link arms. The swirl duct generates a swirl motion in the intake air for more efficient combustion at low engine speed.

and

The engine has a stepless, variable swirl system located on the cylinder head. The swirl system rotates the air in the combustion chamber for effective combustion. Variable swirl enables fine adjustment of combustion, for effective combustion and low emissions. At idling speed, the damper is closed and air rotation (swirl) is high to facilitate combustion of the soot particles.

The higher the engine speed (rpm) and torque, the more the throttle opens and the swirl is reduced, to improve power / performance.

If you are getting an incorrect swirl flap position error, then it can only be the actuator position sensor.
Disconnect the actuator, ensure the connector is clean and free of corrosion.

If all looks OK, consider a replacement swirl throttle (2nd hand or new)