I flew my Mavic 2P in a light rain yesterday. Made a quick vid for you. You can see the raindrops falling in front of the camera.
It looks as if water can get down into the motor windings on the props. I doubt any of the ckt boards are in danger, but not sure. The Mavic seems to have airflow through it's body, pulling in the vents in the front. Not sure if there's some risk of water getting pulled in. I wouldn't fly it in anything harder than a light drizzle, and even that is probably asking for trouble.
I flew it around a bit and the navigation and obstacle avoidance did not seem to be affected by the rain, but if it was harder I'm sure you'd have to turn some of the sensors off (i.e., go into "sport" mode).
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