I did the iOS equivalent of cmd+tab back to the Beeminder app which had the stopwatch running. Happy that it was in fact still actively counting up (I saw it increase by 1, 2 seconds), it then, out of pure spite, decided to crash directly in front of my eyes. I didn’t do a thing! And by crash I mean I was all of a sudden back on the home screen. Relaunching the app took me back to the dashboard.
Here’s a wild theory: Upon reactivation the app starts a thread in the background to refresh its data from the servers maybe? and aforementioned thread causes a hick-up that dooms the entire app. Whatever. It’s annoying though.