Real Time Clock

I have an S2 controller that the real time clock is not updating correctly. It counts up but it takes about 5 seconds before the clock updates 1 second. When I sync the times from the controller to the pc using pac display it corrects this. But after 30 minutes or so the the clock has not moved but 5-10 minutes. I’ve updated the firmware to the latest as well. Any ideas on how to correct?