I'm not entirely sure what you're seeing, but all I see is the normal design of the coin, combined with some unusual damage.
The "crack" you've circled here is just a natural indentation in the coin's design, made somewhat worse by the peculiar damage this coin seems to have suffered - as if someone's sandblasted away at just the centre of the coin and leaving the area near the rim intact, as well as leaving all the protected areas rather dark. But the "crack" is not an error, it's supposed to be there.
The real-life queen's actual face is three-dimensional. A coin is far less three-dimensional. They need to use raised and lowered areas - "ridges" and "cracks" - to simulate depth.
Don't say "infinitely" when you mean "very"; otherwise, you'll have no word left when you want to talk about something really infinite. - C. S. Lewis