All meters should ship with an instruction card detailing the wake-up process. Very sorry that yours didn’t seem to include one.
The meter should not drop back in to shipping mode unless you explicitly tell it to through the app. I expect your Mooshimeter is simply in standby – is the LED blinking once every 10 seconds? If so, the unit is in standby and should be discoverable by bluetooth.
It’s possible you’re experiencing an Android BLE bug – can you try rebooting your phone and scanning again?
Sorry for the trouble, please let me know how it goes