What does this CLI error mean?
Here’s how I got it…
Tried to download firmware to Asset Tracker Electron by CLI (USB).
LED stuck solid magenta. (Previous firmware was actually still running, and doing blinky on user LED.)
CLI showed this error:
Potentially unhandled rejection  unknown message (WARNING: non-Error used)
I reset Electron, tried again, and it programmed ok.
If only there was a way in which you could take an image of your screen and share that…
Since there evidently is not, and we have no idea what commands you’ve used, nor are we able to see the full output, there’s little we can say I’m afraid.
I think the device may not have been in the correct mode (since you say it was still doing it’s thing, which it should not, depending on the mode you’re in), but that’s hard to tell.
I will snapshot screens from now on.