Rattle passenger door air vent

Hello folks,

Please help me on this, i have , on my 19 tdi fabia II , a fantastic car for many reasons, one thing that is making me going nuts.

When I drive low speed I hear a tickle coming from the passenger side, seems in the right side , area of the passenger door air vent)

When I drive at higher speed the tickle becomes a random bump , influenced by air getting in the ventilation circuit from outside because when I close the air ricircle this disappears.

I have read here and there in the forum about problems with the fan radial play that someone here fixed, in Italy my dealer says they never heard about this, please let me know if somebody experienced something similar,

Please help with advices or experiences.

Thank you in advance.