If you really want to know the actual reason the title reads "new erdős paper" it is this:

https://en.wikipedia.org/wiki/Erd%C5%91s_number

obviously this is not an actual new erdos paper, but without these shenanigans everyone's erdos number would slowly but surely increase, as first nobody new could have co-published with him (too young) and soon the same applies to his co-authors.

while it might have been cute back in that era, today I think it should be treated as a historical thing.