There needs to be a verb to describe reading an obiturary, or hearing about a recent death, with the reaction: He was still alive? Or she, to be complete. Happens a lot. Example I read about not long ago: Monty Hall.
I can’t deny that I spent some hours of my young life watching him preside over eager costumed contestants vying for a new car! etc. But I didn’t know until a few years ago about the Monty Hall problem.
For an even more obscure version, here’s “The Battleship of Maine” by Red Patterson’s Piedmont Log Rollers. Recorded in 1927, when the war was very much in living memory. It’s a little hard to (easily) scare up information about Red, but it’s possible.