Part cooling fan always on at low speed

Hello, I have an issue with my Rat rig C-Core 3.1 priter (400x400) cooling part fan. I changed the part cooling fan with this one "https://www.distrelec.ch/fr/ventilateur-axial-dc-bille-40x40x28mm-12v-48-6m-sanyo-denki-9ga0412p3k01/p/30154445". It seems to work quiet well. I can change the speed with PWM control correctly. The only problem is that when the value of the fan speed is set to 0 (when not printing or while first layer) it still blows some air. The speed is very slow but not at zero as expected. I have trouble understnding the issue...

This is my klipper config for part cooling (pretty standard configuration) :

[fan]
pin: !fan_part_cooling_pin
cycle_time: 0.00004

Did anyone have the same issue ?
Was this page helpful?