I flown over water with my Mavic 3 pro quite a bit, and never had any problems. Even when the indicators turn red, and it's only a few feet over the water, it doesn't hit the water. Just don't pull down on the wrong stick.
Take-off Exception
A "take-off exception" on a DJI drone refers to an error condition that prevents the drone from taking off normally, usually triggered by a safety check detecting an issue with the environment, the drone itself, or the pilot's...
I've testing doing it on land, and the drone is stationary when you do it. I guess if a sudden gust of wind came up it could move, but you catch it above your head or face.