I think I know now what happened to the OP - it happened to me today!
Since having video lag etc often on the K1 tablet, I thought I give it a try withe my Google Pixel XL phone (Android 7)
Bad idea!
I managed to go quite some distance over a river, I was standing next to it on a dike.
No signal problems. Just as I turned around the app crashed.
I restarted the app and continued to fly home.
When I checked the flight at Air Data I realized that upon restarting, the Go4 app automatically set a new homepoint - at the AC, over Water!
I'm lucky I didn't rigger RTH. The drone would have gone for a swim.
Since multiple app crashes are being reported, there should be an option in the app:
"Do not record homepoint automatically"
My suggestion:
IF THE APP CRASHES, DON'T RESTART IT! Trigger RTH on the remote!
See top left in the image:
It says "H" for homepoint at the moment where the app was back up working.
My actual homepoint was to the right at the bottom.
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