So it's not design weak points .. it's defectives parts.
I doubt that you know that
You would have no idea what the design strength in any axis is, let alone the expected prang separation points for any design.
You may think that you know only based on inferences in a news story.
Every aircraft and engine has a historic separation point in a survivable prang. They are certainly not the same between aircraft models for the same general impact conditions.
The only thing that maters is that some prangs are survivable within certain G loadings, how they break is immaterial.
This issue, as relayed from the news is a compliance issue and nothing more should be read from the incidents then what is written in the recommendations from the accident investigation