I recently took my drone on a solo canoe camping trip in Canada. I was flying the drone over the lake taking video of my campsite from birds eye view. It wasn't terribly windy that day, maybe 10kmph so the mini was fine, and I was flying in sport mode. I brought it down to hover around 12 feet above the water to take one last shot, and before I could begin moving forward, the drone just started to drop in altitude, lower and lower, I quickly realized what was going to happen if I didn't do anything so almost immediatley I pushed the "ascend" or "up" joystick to raise the altitude of the drone. It didn't respond to any of my input and kept lowering its altitude. It continued to do this as I helplessly watched, and then it hit the water, for a split second after it hit the water it reacted to my up joystick finally, then sunk again never to be seen in the black abyss of cold canadian water. Obviously I'm frustrated, and I felt quite helpless here as the drone didn't react to my input.
I know nothing can be done, but I just at least want to be able to understand WHY it happened. (Is it the VPS glitching over water relfections?) I'll post my flight log and a link to the footage.

The file is bigger then the 1000kb limit on the forum so here's the google drive link
https://drive.google.com/file/d/1thTT8NmbIxYdurP72ozMjmcd2y819KIi/view?usp=sharing

Here is the YouTube clip of the drone hittiing the water when it started descending...
https://youtu.be/kBQdojf03-4

Online Log Viewer link:
https://www.phantomhelp.com/LogViewer/06UTXZ2FVIOJWPM6HEBX/#

Here is the logviewer link for online viewing
https://www.phantomhelp.com/LogViewer/06UTXZ2FVIOJWPM6HEBX/#

benjaminv Posted at 11-3 14:22
Here is the logviewer link for online viewing
https://www.phantomhelp.com/LogViewer/06UTXZ2FVIOJWPM6HEBX/#

Your drone showed difficulty maintaining height from the beginning of the flight.
I've attached a graph showing how poorly the drone maintained height without any throttle input from 11-47 seconds at the beginning of the flight.

15 seconds into the flight the warnings started.
The following warnings appear many times in your flight data:

Aircraft max power load reached. Decrease altitude and fly with caution. If this issue persists

Another warning at 28.7 seconds:
Propeller(s) rotating too fast Return to home and land promptly. If any of the propellers are warped

Aircraft max power load reached. Decrease altitude and fly with caution. If this issue persists, land immediately (Code: 30168).; Return to home and land promptly. If any of the propellers are warped, restart the aircraft and hover in a an open area for 5 min or longer to try and straighten the propellers. If the issue persists, replace the propellers or contact DJI
Is it the VPS glitching over water relfections?
VPS was measuring the height of your drone as it descended to the water, but the propellers were deformed and unable to provide the lift required to climb.
This also affected the drone's pitch angle in the times where you pushed the right stick full forward.

Hello there benjaminv. I am sorry to read and to know what happened to your DJI Mavic Mini and thank you for reaching out. Since this unfortunate event happened I would recommend you to contact our DJI support team at https://www.dji.com/support?site=brandsite&from=nav for further assistance. We will do there best to evaluate the said DJI drone and will give out the best resolution for this issue. Again, I am sorry for the trouble and thank you.

DJI Stephen Posted at 11-3 19:26
Hello there benjaminv. I am sorry to read and to know what happened to your DJI Mavic Mini and thank you for reaching out. Since this unfortunate event happened I would recommend you to contact our DJI support team at https://www.dji.com/support?site=brandsite&from=nav for further assistance. We will do there best to evaluate the said DJI drone and will give out the best resolution for this issue. Again, I am sorry for the trouble and thank you.

Thanks Stephen, I'll try to reach out to them over email. Appreciate your help.

Labroides Posted at 11-3 15:30
Your drone showed difficulty maintaining height from the beginning of the flight.
I've attached a graph showing how poorly the drone maintained height without any throttle input from 11-47 seconds at the beginning of the flight.

Thanks so much! I was wondering if that was something that would impact the performance. I'm surprised it actually started descending without any warning of its intention to do so however.

benjaminv Posted at 11-4 09:04
Thanks Stephen, I'll try to reach out to them over email. Appreciate your help.

Hi there benjaminv. You are very much welcome and if you have any other concerns or any inquiries with DJI. Please feel free to post it here at DJI Forum. We are all here to help and assist you. Thank you.