clock slows down

[JoanaRibeiro]

i bought a sony xperia v this week and ive noticed already 2 times in the morning when i woke up that the clock was 20min late one day and 7min the other day. I didnt have activated the option Automatic date & time. I just have activated the option standby mode. I presume it has somehting to do with the standby mode?? 

[Hampus]

Does the clock show the wrong time even when you unlock the display and check at the clock in the top right corner next to the battery icon? Or is it the clock that you can see when the display is locked that shows the wrong time?