FP2: I have now experienced that the clock on my phone says something wrong - usually it is ½-1 hours wrong in time after I have opened it. This is problematic, because I do this every second week or so (have to do, otherwise the sensor close to the ear will not work because I have to remove dust around/on it). Usually it lasts for ten minutes and then goes back to normal - but this last time it has lasted all night - and actually made an awkward situation personally.
What can I do? I do not want to get late for for instance a job interview, the train or a wedding :-/
I’m having the same issue, when FP2 is without battery 15 minutes or so. Sometimes the timesync doesn’t work or needs endless time. Workaround is to switch off the automatic time setting and set the time manual. I have not tested if time drifts with the manual setting too, without battery.