If you still have the original LCD screen, put it back in and see if it does the same thing. It might be a defective / bad 3rd party screen you have there, or it has been damaged. A similar sort of white to gray vignette and vertical lines problem happened to my LG Optimus L90 - that is, after I put it through some physical stress tests.

given a moto G3 to fix as it wasn’t displaying anything but makes noise, originally thought it was a screen issue so i ordered a replacement but with the new screen in, the same problem persists.

the phone vibrates and makes noise but the screen doesn’t display anything nor does the backlight appear to turn on. is it a problem with the small ribbon cable that extends the screen connector on the logic board maybe?