Was out flying last Sunday at Lake Havasu, AZ testing out my new Polar Pro filters when my beloved P4 suddenly dropped down to 0 ft according to the flight data lot into the water. I was flying at 20 ft filming a boat then decided to break off, tried to make a turn to the left to come back around but suddenly I got an alarm, beeping sound and then more beeping sounds. This all happen very fast. At that point it dropped to 0 ft and dunked the camera for about 4 to 5 seconds. I hit the RTH the P4 did climb to my set altitude of 40 meters or 130 ft. It did come back and I took over the landing because the shore line was small. The P4 acted very erratic during the landing. I pick up the P4 and water poured out of the camera area and under the quad. I did not have tools with I dried off best I could and let it set out on the rocks in the sun. Temp was about 99 deg. pretty warm. When got back to the house I did remove the lens cover and I did drop down the lower cage assembly. Did not see water or any condensation. At this point, the camera gimbal does not function. It does turn on but do not want to fly until things are corrected. The distance was maybe .1 to .2 mi. and both RC and bird had full bars. I show the following errors in the Overall Status: Gimbal Roll Error Hardware Malfunction. Contact DJI Support for repairs. Gimbal Yaw Error Hardware Malfunction. Contact DJI Support for repairs. View attachment 55822 Also this is the second flight since I did a IMU calibration. The first flight the RC screen would flicker and same for the second and last flight. Anyway suggestions as to what may have happened? I have a video clip but so far cannot figure out how to up-load to show.... Thanks for any and all support. This was my 11th flight, the only advanced option I have tried was the Around Me. I had a P3P for about a month and it flew great.