Gotcha. I am using a repeating timer in this particular app. OnTimerEnd, Lat/Long (and a WHOLE bunch of other data) are written to Azure SQL. I'm still testing what happens when the screen goes to sleep/app is closed/home button is pressed/phone is turned off while the timer is running. It appears the writes to SQL just cease. This is the issue.
I really like your idea for showing a "last saved" label.
My iPhone has many signals that show when its is locked/asleep/etc.
For anyone interested in looking at the data their iPhone is capturing:
Scroll to bottom, click Analytics
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Peruse these logs! Very interesting!
There are parameters like "ScreenIsLocked", "TimeSinceLastLock", "DeviceIsPowered" etc that would be HUGELY beneficial for us to be able to tap with PowerApps.