I lost my first drone in 6yrs last week, fortunately is was my Mini2, my least cost toy. The craft was lost in a river as I was flying about 6' above it, capturing ducks floating in the river. I was hoping someone in this forum could do an analysis on the flight record to disclose the details of what happened at the very end. I was flying about 400' away with clear VLOS. There were no obstacles in the middle of the river where I was flying. I have flown this area of the river many times so I know it well. However when I was flying, all of a sudden the screen picture jerked erratically then went black. I looked up VLOS and didn't see the craft anymore. It vanished. I looked back at the iPad an I saw "IMU error" message on the screen. I pushed RTH in desperation, but as expected, no joy. When I reviewed the iPad video cache it looks like it went into the green water. The color shown in the last frame on the video was green, showing streaks like a splash. Even though I had a refresh policy, I was denied refresh replacement because I couldn't retrieve return the craft. DJI denied and IMU failure warranty, saying there was no indication of IMU failure in the flight record. I'm unsure how that can be true if I saw the message on the screen. I would think a record of that message would be in the flight record. If someone could analyze this flight record I would appreciate it. Thanks much.