I would have expected it to do an automatic re-sync with a device. If it doesn’t report the time, one has no way of knowing if a user-initiated sync is required. Brilliant.
That still requires the app to be opened. So if you don't have the app open when power comes back on, you're out of luck. And if you're in another timezone (on vacation, for example), then a time sync would reset it to your *local* time, not the local time of the unit. Also a problem. Even without a clock battery, I would think the unit should be able to reach out to the Internet when it powers up, and pull the correct time for it's set location. But they didn't write the software that way. And they probably never will, unfortunately.