What's up with the Mandela Effect?

Some people think Nelson Mandela dies in jail in the 80s, and remember his funeral being televised. He in fact lived until 2011 and only passed after a distinguished career as a diplomat and philanthropist. Same thing with Billy Graham, who as far as I know is still alive. And then we have the whole Jif / Jiffy peanut butter thing, but I won’t go there, it weirds me out too much… Elucidate, illuminate, regurgitate.