Leap year problem
Issue resulting in miscalculation of leap years / From Wikipedia, the free encyclopedia
Not to be confused with Julian calendar § Leap year error.
The leap year problem (also known as the leap year bug or the leap day bug) is a problem for both digital (computer-related) and non-digital documentation and data storage situations which results from errors in the calculation of which years are leap years, or from manipulating dates without regard to the difference between leap years and common years.