Settling With Power (Also known as Vortex Ring State or VRS) isn't created "hovering over water" but a condition when the aircraft is descending into it's own "turbulent air". In most basic terms the rotor(s) are slipping in the messy air and causing the aircraft to be unable to maintain lift/control. Basically you're descending into your own crappy air and slipping to terra firma quickly.I’ve only experienced that with my M2 when hovering over water. But, that was due to the sensor and the subsequent “LANDING” announcement. I was able to easily recover by commanding a climb from about 15’ above the calm, glassy water.
This was an issue with early DJI and other brands of UAS before they tweaked the Flight Controller settings to help reduce/eliminate this possibility through limiting Max Descent Speed. This is why the aircraft seems to descend slower than what you might think it could/should.Just curious. Are quadcopters troubled by "settling with power" like conventional manned helicopters?
You can still get into a variant of VRS with non "Limited Flight Controlled UAS and large UAS but it's usually not nearly as big a deal for MultiRotors as it is with single rotors (Helicopters).