Imagine if I come into the possession of 80 severely damaged Chanel handbags for super cheap. They’re basically shedded, but they have intact branding.
I go to China and get 80 replicas. Then, I carefully cut the genuine logo, off the ruined handbags, and sew it onto the replicas.
Have I committed counterfeiting? Under the law, 100% indisputably; despite using a genuine logo from a genuine handbag. Despite me legally purchasing both items, the combination is, in a sense, illegal. I would risk up to a decade in prison if I sold that combination.
Now replace handbag with iPhone screen. The distinctions become extremely difficult, and not the CBP’s job to figure out. Surgical legal changes are required.