Right, case-by-case... that was mentioned by the article. And as far as I can tell, the only reason they would NOT honor the warranty on the rest of the phone, is if there is obvious "tampering"/fraud. Like swapping logic boards or other internal components to try and trick Apple. If you truly replaced ONLY the screen and then, at a later time, had a hardware issue, I find it unlikely (as in my case) they would deny warranty service.
My non-OEM screen was working perfect. I was having charging/battery issues with my old iPhone 8, a couple months after my screen was replaced, and they went ahead and replaced the entire unit, including the aftermarket screen.
Prior to this internal memo, if they even saw a non original screen on a device, they would immediately tell you they wont service it, no matter the issue.