I had a spot on a Paperwhite3 that was like an LED shining straight through. It was invisible till you hit the right angle, which you always did reading a page. Kindle replaced it immediately and I couldn't have been happier with their response.
The Paperwhite is a year older and is fine. I have two, actually, and they're both fine. My Voyage was fine until I gave it to a friend and I suspect ti's still fine.
Remember the Forest Ranger in the Smokey National Park who kept getting hit by lightning? His name was Roy Sullivan.
"...Sullivan was hit by lightning on seven different occasions and survived all of them."
https://en.wikipedia.org/wiki/Roy_Sullivan
As the saying goes, really weird things happen and whenever anyone says, "It can't be a coincidence, they're always wrong.