No, it doesn't mean that. Almost everyone's computer system clock is kept synchronized to a time reference by the computer's operating system. Normally, that time adjustment is, at most, a few seconds and doesn't cause any problems. The problems are introduced when the computer's system clock is unreliable, either because people are using it as a "calendar" to check dates (that happens more frequently than you might imagine) or because of a computer problem, such as a depleted CMOS battery.