I was on a intercontinental flight to the US and noticed this object shaking with the wind and moving as the flaps change position. Is this normal? I have never seen this before. Is it safe to travel with this kind of item on the trailing edge?

I was on a intercontinental flight to the US and noticed this object shaking with the wind and moving as the flaps change position. Is this normal? I have never seen this before. Is it safe to travel with this kind of item on the trailing edge?
