neo 2 fan noise and stop/start.

hello

I have a neo 2 and found that it has a sound from the fan, but i also noticed that the fan behaves weird.

It stops/start sometimes and then continous to spin, and the sound that the fan or electric controller makes seems to follow the stop/start procedure.

It's only the fan closest to the bottom bracket that behaves like this.

Don't know if it's normal? What do you think?

I have a link to a video here, please use headphones:

https://www.youtube.com/watch?v=S815qzDdqEk