I have no knowledge, but this seems like an error, not a leak. It is very common for publications to pre-write news stories, based on things that might happen. Perhaps this was one of those that was posted accidentally for a few minutes. I once knew the guy who did the covers of People magazine, he had covers ready for the deaths of over 100 celebrities who were very much alive.
I’m skeptical too but then I was predicting Biden would have been long gone by now so who knows for sure.