Greetings - I just recently purchased a Phantom 3 professional from an individual who had only flown it twice (allegedly). The story appeared to be true as everything appeared to be brand new. On my second flight I noticed that the top of aircraft cover had a wear mark in it, turns out it was from the propeller constantly hitting it as it rotated. After further inspection I discovered a completely loose motor were almost all of the screws were ready to fall out. It also turned out that all of the other screws on the other 3 motors were loose as well. Just wondering if this is common, a manufacturing error or something that might have happened before I purchased it. Everything is tight now and it seems to all be good, just curious if this is something that I should constantly be on the look out for!