The old saying holds that there is no point expounding the finer points of ballistics, for the benefit of a man who just killed a bear with a baseball bat. I would be that lucky man who downed the bruin, in the sense that I have not experienced one single mishap over 600 cumulative miles of flying my old Phantom 3 Standard, exclusively with non-DJI batteries.
Bought my P3S back in 2016 brand new, along with a couple of brand new OEM DJI batteries. Didn't get around to flying the drone until this year 2020, by which time both DJI batteries were dead and beyond redemption. Unwilling to drop a hundred bucks apiece for DJI batteries, I went with new, non-DJI batteries acquired from ebay, and haven't experienced one single problem of any description ever since. I currently use three such batteries, of which two have well over 40 charges apiece, with zero problems to report, knock on my wooden cranium.
I attach here my flight log summary. Note that Air Data does not include all miles flown beyond signal range of the controller, but does tally the cumulative hours flown. Given that I only every fly fully autonomous Litchi missions that are 90 % beyond signal range, and that all those missions were flown at the nominal cruise speed of 17.9 mph, simply multiplying my drone's total hours aloft, by the cruise speed yields the equation 35.6 miles x 17.9 miles per hour = 655 total miles flown, ALL with non DJI batteries.
CutFlowers, sir, your experience with after market drone batteries obviously differs from mine, but that does not necessarily imply that ALL non DJI batteries are destined to fail mid-flight. I agree that there might be an element of luck in selecting a decent brand of non-DJI batteries, and that is why I provided a direct link to the ebay seller whose replacement batteries have served me so well, over so many uneventful miles.