Chosen Solution
I just replaced my iPhone SE screen with an iFixit replacement. I did a quick check when everything was plugged back in, but the screen & case NOT snapped back together, and it all looked great. But after snapping the case back together, I now have light vertical streaks on the display! Otherwise, everything seems to work fine (home button, ID, camera, etc.). I re-opened the case, disconnected the battery and display connectors, re-connected everything, and re-tested - same result. . . TWICE! arrrgh! So, did my new screen somehow get broken, or is there another possible cause?
The flap you are referring to is the small metal prong that kind of clips into the display. There are two prongs that go over the earpiece speaker to hold the front camera and speaker in place which is also held in with two screws. The right prong clips into the display and the left prong also does the same, but that one must be put in properly or it can pierce the display cable. It could be that when putting the screen into place it may have been put in with too much force. As long as the corners of the iPhone’s metal housing is not dented inwards where it could make it difficult for the screen to go in. It should be fine while taking note that the screen hooks in from the top first then bit by bit work your way down pushing it into place while applying a bit of upwards pressure to make sure the screen is pushed towards the top to make it easier to clip in as you’ll be doing the bottom last. Once it pops all the way in it should have no problems, it sounds like a defective screen. Sorry about the long paragraph but that is my experience from doing iPhone 5 series screen replacements over the years.
Behind the aluminum shield, at the top there is a flap that runs down, it is part of the flex cable for the earpiece, make sure that it is behind the shield, not in front. At the top, where the red film cuts off in the middle, there is a flex cable, that if you leave outside and on top of the metal shield, it will cause interference.
Apparently, it was a bad display after all. When I installed a replacement, everything was perfect!
