Are the hardware specs for the MFT module (I think it's called an "APIM") available? Does it have, for instance, a real-time clock in it?
I could see software that gets busy and fails to update the display regularly. But time jumping ahead or back or drifting seems to suggest that the time is being maintained in software, driven perhaps by some timer interrupt, and it would be missing that interrupt or having the storage for the time value overwritten (eek).
If there's hardware out there ticking away -- as with the GPS in the nav module --, and software reads it to display, then the worst that should happen is that the display isn't always updated.