not the first time (nor the last unfortunately) that engineers doing a "what if" assessment under part 25 assume the best in reliability from vendors who have promised the sky (95% free from defects) without actually auditing the vendor's output until a serious failure has occurred.
We are doomed to repeat this type of shortfall over and over in spite of the paper trail between the FAA and the prime manufacturer.
The most common form of this lack of oversight are presumptions of Freedom from hidden "gotchas" in a design was supposed to be "fail safe" against common faults.