See the "Losing Time" post from a few weeks ago: Losing Time | PriusChat I have been having the same problem, but this happens over the course of a month, not every day. Yikes.
Different oscillators or crystals would make them behave differently. 1 minute a day is 1/1440 (0.0006944) or 0.06944% wrong. It is rare for all clocks to line up, that's why internet or radio enabled clocks and devices re-sync every so often. For example, your PC re-syncs every week, some every night. Turn that off, and your clock will be very wrong, very fast. Is there no "set time from GPS" option on the PiP MFD?
Mine looses 2-3 seconds a day. Good thing they added the :00 button so I can sync with hour tone on the radio while I'm driving every so-often.