Bizarre 2016 One Pound Coin Is It A Fake?

Hello and

From the photos it's hard to tell if the coin is genuine or a forgery. We'd need larger, closer photos with the micro-lettering that's just inside the rims visible. If this is missing on the coin, that normally means it's a forgery, although it could be a weak strike.

My initial feeling is that the coin is genuine but has environmental damage, maybe from being buried or kept in a damp place. Nickel-brass tends to go dark in such situations.