I just got a Phantom 4. Looking it over, I noticed that the metal grill covering one of the two ultrasound sensors on the bottom is dented - it is curved inwards (concave) as if someone had crushed it by pushing hard with their finger. Will this affect the performance at all? Should I consider exchanging it? Seems fine otherwise. The grill doesn't appear to be in contact with the sensor behind it, but it's pretty clearly bent.