However this all seems to have been some sort of surprise, and it shouldn't be.
This is he primary problem as I see it. The fact that the spec/design/test process appears to have a large hole in it through which this bug slipped needs to be investigated further.
The whole GCU reset every 248 days, by itself, is a non issue. That (like many other maintenance items) can easily be taken care of once the issue is known and few people would care. Some might. Every maintenance step, no matter how trivial, incurs a cost to document and track at the operator's expense. So even one extra check box would raise a few questions. Particularly if they understood how trivial the fix would have been back in the design stage.
But what with the industries increasing reliance on manufacturers self certification and the regulators hesitance at questioning anything process related within a company, I'm not hopeful that other bugs haven't slipped through as well.