Hmmm this is interesting. Because I've long had the complaint that notifications are frustratingly ephemeral. There have been many cases where I've gotten a notification that my phone clearly has but which I can't read, because when I tap it, it's purged permanently, and then I have a spotty internet connection, so I can't see it in the actual app that loaded.
I'm always like "JFC, can't you cache the notifications, so I can see it there while waiting for the app to gets its act together?" But no, that's never an option.
So I'm getting a laugh out of how notifications last long enough to be extracted by someone just not the person that they're for. (Though to be fair, it could be a case of a notification that was never tapped, and therefore hadn't been purged yet. I couldn't tell from the story.)