Just bought me new ATT Galaxy s10e and IT HAS a Samsung factory installed screen protector! I can't tell you if mine is some kind of fluke, but on this new s10e its there. Jus sayin...
Did not know there was some issue if it has one or not. Every new phone I got has a plastic protector on the screen, usually it's a temporary one but there is no need to remove it if it's clear enough.
I'm not talking about the shipping plastic protection, just peel off and throw that crap away.
Mine you have to look real close to it around where the front cam lense is and the ear speaker areas to really see it good.
It's worth noting that the factory installed screen protector does not play well with polarized sunglasses. The first time I tried to use my phone outside in the sun with my Maui Jim's on I realized how terrible the screen looked. Only way to fix it is by removing protector and using a different one that doesn't impact polarized lenses.