So I'll start off by saying that before I take off I always inspect my props to make sure they are in good shape and not damaged at all, so there is no way my propellers were like this pre-flight. Two days ago after landing my drone I noticed that the propellers had sustained some pretty bad damage. All four of them are worn on top of the hub almost as if they were spinning against a ceiling which is impossible as I never came close to any structures while flying nor was I inside. One of them is also very badly chipped and another two are scraped up and have some black streaks on them. Like I said I never came into contact with anything, and after I noticed the propellers I thoroughly checked the drone and there were no signs of a collision with anything during flight. Does anyone have a clue as to what could have caused this? The drone flew fine the entire time and I wouldn't have noticed anything was wrong if it weren't for the obvious damage on the propellers.