This happens near water, on a D5500, the autofocus goes completely, utterly out of focus. It happens repeatedly until I completely shut off the camera and restart. After that, if I shoot very quickly at something else randomly (my foot, up in the air, etc) it's OK and will do a normal waterfront picture. Manual focus doesn't help. It's OK in other situations and, most of the time, it's OK near water, so this just happens at seemingly random intervals, always waterfront.
The camera has a stock kit lens, 18 - 55 zoom and it works fine everywhere except near water. The other night, I was shooting at a big Baltimore night event on the waterfront with all sorts of lights and festivity and shots with lights illuminating harbor water made it go bad again. It's not just at night, daytime too, bright beach shots. A "reboot" fixes it for the moment, but it is aggravating to miss a shot and not know when it will happen again, except for the part of being at a waterfront location. Farms, cities, etc, are OK.
What gives?