A1 2019 Sportback: Noise from the back when air is off

[misterbirra]

I everyone, I've got an used Audi A1 2019, 25 TSFI Sportback. I've discovered a noise coming from the back of the car, only when the air is off.

This noise is like a "flap" of a rubber surface over a plastic part. I've discovered the reason, and I made a video of it.

What do you think? Is that normal? In my opinion...seems like a "design issue" 😐. I will go to an Audi center in 2 weeks, in the meantime I ask your opinion... thanks!