Ran a simple Litchi Orbit with the “Remote Controller” set to “F” as required. The orbit was perfect around an old oak tree I get in many seasons and when finished, I switched the Controller to “P” to see some other stuff around the neighborhood and my drone took off to the East at 5 t 7 mph! The wind was calm. WTF? I hit the “Home” button and it behaved perfectly coming home, but why did it run off like that? I have never had my P3A do this and it makes me nervous.

why did it run off like that?
You would have to post flight data for anyone to be able to answer that question

I have never had my P3A do this and it makes me nervous.
Finding out what caused the incident is the key to flying with confidence again.

Labroides Posted at 5-29 17:38
why did it run off like that?
You would have to post flight data for anyone to be able to answer that question

OK, Captain, how do i do that?  

bob37 Posted at 5-29 19:52
OK, Captain, how do i do that?

Follow the directions at:
https://www.phantomhelp.com/LogViewer/Upload/
Post the link to the report it provides

Here it is:  https://www.phantomhelp.com/LogViewer/R651OZDNMIYRMPXE8EM5

In looking at the data, i see that after the Litchi "orbit" the drone went to "Atti".  I meant to switch to the "P" setting to get out of the mission.  Is Atti sort a free flight mode so was just drifting with the wind?  Perhaps i did not push the little switch far enough.  

bob37 Posted at 5-30 05:53
Here it is:  https://www.phantomhelp.com/LogViewer/R651OZDNMIYRMPXE8EM5

There does not appear to be any data in that link.

I just tried it - you click "download flight log" and it does it sends a csv to your download folder  - at least on my computer.  

bob37 Posted at 5-30 14:33
In looking at the data, i see that after the Litchi "orbit" the drone went to "Atti".  I meant to switch to the "P" setting to get out of the mission.  Is Atti sort a free flight mode so was just drifting with the wind?  Perhaps i did not push the little switch far enough.

That does appear to be the explanation for what you described.
You had GPS with plenty of sats but the Phantom was in atti mode.
Atti mode ignores GPS, which leaves the drone without horizontal position holding.
In Atti Mode, it will be blown by the wind and won't have "brakes".
RTH worked even though the flight mode switch was in atti, because RTH is a different mode and satellites were available.