Fan squeaky noise when shutting off from motor compartment

On my Gen3 (2 years old, about 40.000km) I have noticed this noise coming from a fan, which I suppose is the A/C Fan from the front of the car behind the bumper.
The noise is not present when the fan is rotating, only when it slows down when it gets switched off.

When A/C is off, I don't hear this (typically the other cooling fan for the ICE is off by the time I get to park my car).

I started to notice this now because I need to open the garage doors to park the car - it is usually very quiet and this is how I managed to spot this. It might well be that it has been around since I have bought the car....

What do you guys think? did anyone notice this?

PS: I wanted to post an MP3 file of the noise but I cannot. Which format can I use to post a sound?