Patriot and requirements
As noted earlier, the bug has a great deal in common with the Patriot Missile failure. What is important is to note that the Patriot software wasn't in error. (It wasn't a clock counter wrap, but rather accumulating error in the clock.) The mistake was way back in the system requirements, where the specifications called for an agile system that could be rapidly deployed and moved as needed. The requirements called for a system that could remain stable for about four days. Nobody though that there would be semi-permanent emplacements set up to protect military bases. So nobody added a time span to the requirements.
So, how far back in the system requirements analysis for the GCU was there an explicit expectation for how long the system would stay powered up for? These are the places where issues slip between the cracks, not some poor programmer who was asleep at the wheel. With Boeing outsourcing so much of the systems, it isn't hard to see how hard it is to keep things like this under control. As the 787 is the first airliner to have such a massive reliance on electrical control, it isn't hard to see how traditional expectations of system up-time would influence the analysis done by many engineers.
I bet an analysis of how this bug came into existence has vastly more to do with the difficulties of requirements across many contractors, and much less to do with "obvious" coding errors.
Biting the hand that feeds IT
