These overprints can be pretty variable in how they get printed but note where the legs of the "h" and "n" attach, they're in different places = different fonts/typefaces. The tops of the "e"s are different, too. I'm thinking it's a forgery. If someone has a Maury catalog, perhaps they can add something here.
I doubt It is forgery to cheat the collectors as both stamps *with and without OVPRT) are same catalog cheap.
It doesn't always work like that. You probably know that complete sets are often easier to sell than singles. Someone can put in a couple of forgeries to complete a set. And then there are stamps used to test the look of forged overprints before forging inverted overprints and other errors.