iPhone 8+ and upper left corner of screen: proximity question
I'm still running the latest version of iOS 11 and I've noticed this for at least 6 months.
When I go to touch the screen in the upper left corner (where the "back" indicator is for example), my screen often turns off. I don't actually have to touch the screen, just come pretty close. Any one else see this?
Ugh... that doesn't sound good. I would definitely try updating to iOS 12 to see if a software update solves this issue. I don't expect that it will, but that's also the first step that the Genius Bar would likely take, so you might as well try it first.
Failing that, though, I think it's time to either send it in or visit the Genius Bar. The Apple Support iOS App is a great place to begin... assuming it doesn't require you to tap that part of the screen!