When I was real young I would ask my grandad if he knew what was for dinner, he'd usually respond with "Shit On A Shingle." For the longest time I thought he didn't know and was just responding to the question with the least appetizing thing he could think of.
Decades later, working on the road, there was this lady who'd cook up huge dinners and sell plates for like $5 so you didn't have to leave the lot to get food. One day I asked her what was on the menu and she said "Shit On A Shingle" and I replied "Oh, so you don't know yet?" and she said "No, I'm making Shit on a Shingle" and I learned that it's a real dish. It's not bad. Genuinely the worst part of shit on a shingle is how it looks.
A little tangential, but when I was very little my parents had a dog and one day they "sent him up north" and then shortly after we got the dog I remember as my childhood dog. Obviously I spent most of my life thinking the dog had passed and they did they "we sent him to a farm upstate" thing. I mentioned it in passing when talking to my mom awhile ago and it turns out they really didn't like the dog but a family friend that lived in the woods up north loved him so they gave him the dog.
That's gotta be the best possible version of this phenomenon.