Unbelievable! I spoke with Apple a second time today, after finding out that my brother was having the exact same issue as me with our iPhones. Namely that we archive a bunch of mail messages, put the phone in our pocket, carry on with life, and then when we next take out the phone the screen looks like this:
This was from a video I took to "prove" to Apple that the issue is happening. What comes next is I have to tap the UNDO (hard to read but it's the choice on the right, below the "Undo Archive". Historically I randomly tapped both that and cancel since I didn't know why I actually had to "do" anything. Eventually, with multiple (a LOT of multiples) taps the screen would get less and less dark and I'd see the mail app more and more clearly and then, eventually, it'd be totally clear. And lots of mails that I had previously erased were back! Unerased!
It turns out that the second call to Apple, forwarded to a senior advisor, got a result. Namely that this is a FEATURE! It's a GOOD thing! They MEANT to drive their users insane.
And to stop it happening, all you need to do is make sure you hit the power button before putting it in your pocket. Something I never ever had to do in the past. But now? Well, if I don't want to be staring at a black screen, now I have to. As do you, I suppose.
I don't want to jump the gun but it's possible this is the dumbest feature yet unveiled by Mother Apple. I'll have to think about a bit before I can state it categorically.