Had this happen a few more times, more frequently in the cold snap, than the slightly warmer weather we've had for the last few days. Battery always around 12v, when I get into car though, where as when the app works, it is usually 12.5v or more.
New development though, if this does happen it is worth trying to turn the AC on even though the status check has failed. Twice now I have had the app report a fail for both the status check and the AC, however the AC has come one, which in turn has topped up the 12v battery, and got the system working again.