Not surprising to me. It was probably contracted out to multiple subcontractors with heavy top down design and review process. Each module is reviewed but th

Not surprising to me. It was probably contracted out to multiple subcontractors with heavy top down design and review process. Each module is reviewed but the reviews can not locate the bugs. Sometimes they hire junior programmers who would have the latest stuff in their resumes but the kids are into copying and pasting stuff from internet not knowing exactly what the code does and they don't have enough experience producing clean and bug free code themselves. Other times the top/down design produces code that lacks elegance and resembles what truck drivers would produce with too many people working on it and no one responsible for the whole thing. Have seen that before. Not sure about this case.