Yes, I have discovered this some time ago, and I also found that while the Newton OS clock can show future dates in its software calendar pop-up slip, I can't actually set the system date and time beyond January 5 2010 after 2:00 AM.
Trying this will cause my Newton to crash, or the date wraps around to December 28 1975 or thereafter.
it seems that without a patch to Newton OS, the system has hit an internal limit that prevents it from representing dates beyond January 5th.
Does this mean it's time to lock up my MessagePad in a glass cabinet?
--tonza