It seems appropriate to link to an old thread, in which the digital clock/calendar in a Doper’s old Hyundai gets confused about a leap year.
The date changes from FEB 29 to Feb 30, to Feb 31, Feb 32, Feb 33 etc, etc.
Two months later the display shows “FEB 99”.
And then, it gets …interesting. 
https://boards.straightdope.com/t/the-most-useless-accessory-in-my-car-is-now-even-more-useless