Lost M2Z, new pilot, unsure what went wrong

[Fly Dawg]

It simply stayed in one place on the map.

If you scroll through the replay of the flight, you can see the aircraft was responding. You continued to fly during autoland until it hit the ground. If indeed you were issuing RTH commands, these were after the end of the data file. Flying BVLOS is never a good idea, and in fact is against FAA Regs. So, I would chalk this one up as a lessons learned.

 

[Lon Denard]

I did, but the location was inaccessible without a boat and some other equipment. What is "OA?"

Obstacle avoidance.

 

[Meta4]

Flew about 20 flights. Read everything, still trying to digest it all, but I'm trying to be diligent. I flew out over a salt marsh in late evening. Received notification on Smart Controller that signal had been lost. Maps showed drone in one place. Hoped RTH would kick in, but no such luck.

The flight data shows you flying 3800 ft out at 395 ft altitude and autolanding is initiated at 4:14.4.
The battery has plenty of juice, so that's not what the drone was autolanding.
What did you do once the drone was 3800 feet out?
Did you try to initiate RTH with the screen button and accidentally press the screen button for auto-landing which is just above it?
This is the most likely explanation for the landing.

Just like any automated flight mode, Auto-landing can be cancelled and you can resume control by flicking the flight mode switch out of P-GPS and back.
It appears that you never lost control as the drone was responding appropriately to your right and left stick movements.
But you never cancelled the autolanding so the drone kept descending until it landed.
The flight data shows the drone at an altitude of 6 feet when signal was lost.
It will be waiting for you at N31.99691 W -80.86410 (if no-one gets there before you).

I'd suggest care is needed with the screen RTH button and you should practise cancelling RTH or autolanding so you know how to do it when you might need to.