I received my MA2 about a week and a half ago and today noticed it seems that the rear visual sensors are not working. When in "normal" mode I cannot properly fly in reverse. It insteads will slowly move backwards and up at the same time all while beeping constantly as if there is an obstacle there. If I turn off collision avoidance or enter "sports" mode it flies in any direction without a problem. I have tried cleaning the two sensors back there and nothing has helped so far.