I’m not sure who made it. The key word is “connects”. It
could have been made by GE or Boeing or a third party. And was in made to spec or not? If it was, who wrote the specs? Were the specs wrong? Was some detail overlooked or miscalculated?
The Prime contractor creates a Spec Control Drawing or a Source Control Drawing for any fabrication to be offloaded to a subcontractor.
In both cases, the prime (GE if it's the engine, or Boeing if it's the strut) owns the design and ultimately, the QA compliance to engineering requirements even though a subcontractor may perform the component fabrication.