Both a simple clock and kinetic scrolling are fairly straightforward to program. Mobile devices don't have simple clocks though. They need to track time zones, daylight saving time, leap years, exceptions to all of those, and users that move between locations observing different times and rules. Mix in calendars that need to track alarms and appointments in the midst of all that, and the situation can get hairy.

As the iPhone has made news with similar clock bugs on several previous occasions, it's perhaps a bit surprising that Jobs hasn't made a complete review and correction of the clock code a high priority in his own, special way, but it doesn't surprise me that there were bugs lurking in the clock code in the first place.