If you got that after installing an app, please contact the app's author. If you haven't installed anything, you should probably contact Garmin Support.
Thanks for sharing the idea. I managed to find out it was actually a prompt for me to update my Connect IQ installed on my phone. It has not come up again after I updated the app :-)
I switched watch faces, and IQ! disappeared. Switched back to favorite watch face, it reappeared. So this looks like a watchface crash for me. Will probably go see if there's an update to that watch face...
