Meh, that’s almost certainly a red herring.
I don’t know The Nation’s motivations, but the date change is probably an artifact of the way computers work. The computer is programmed to automatically insert the date that the article was re-posted.
If The Nation wanted to be more discreet, they could have “re-written history” to show that it had been posted on the original date. It’s entirely possible that you need a computer/database expert to get that done, though.