"Unable to Open App" message

I have an activity app. It runs the first time without a problem, but when I try to run it again, I get "Unable to Open App" "Close the [watchface name] app and try again"  displayed on the screen.  I switch to a different watchface and try again, and it complains with the new watchface name.  Even with Garmin built in watchfaces the problem occurs.

My activity app reads sensor history, does activity recording, writes to custom FIT fields and uses timers.   

Nothing strange, all of which I have done before.  What is the problem?  

Has anyone run across this?

Post Edit:  Actually going back to an activity app or any Connect IQ app that was working before, even Garmin's Connect IQ Store app, now seem to exhibit the same problem.  Perhaps  a firmware upgrade related issue?  Using a Fenix 7.