This happens most often when someone launches tentatively as opposed to just gunning it until it's at least a couple of meters high.my P3 advanced flipped upside down on launch.
You didn't say what steps you took to try to stop the motors, but in most of the similar posts it was a CSC that failed to stop the motors when the AC was inverted on the ground.I could not shut the motors down.
Any tips on how to shutdown under these conditions?
A couple of people didn't think to try that and pulled the battery, but that's a bit scary with the props going.