I've noticed that some of the dates entered, if too far in the future will revert to last century.
i.e. January 5th, 2050 will work correctly if entered as 01/05/2050 but will think it's January 5th, 1950 if you enter 01/05/50
Also, once you enter the date as 01/05/2050 and it is shortened to 01/05/50, if you edit the date by hand (change from the 5th to the 6th by highlighting the day and pressing six on your keyboard) the date's year will revert to the 1950s.
I don't know how one would go about making sure each date field is pointing to the correct millennium, but it worries me to think that I may accidentally send a customer an automated notification that their bill is about eighty years past due and the late-fee is enough to start a lunar base.