Not the best adhesive color match at the seam, but the whites are the most difficult. Looks like someone left some black buff pad marks on that edge crack. The cracks are the nature of the beast.

When you examined the slab and signed off on it, you did not notice any of these marks?

This is an interesting article to help you decide if what you see is a fissure or a crack. Fissures are , as Joe said, the nature of the beast. You can tell the difference using, of all things, your fingernail.

https://www.hardrockstoneworks.com/blog/20/the-difference-between-cracks--fissures

Thanks for your replies. I checked and it’s a crack on both sides. I didn’t see any marks. Can anything be done about the adhesive color match?

A seam that wide will pick up some contamination over time that will make it less conspicuous.

If the seam is fat enough, you may be able to dig out the adhesive with a Japanese pull saw and replace with a beter match.

How about a more close-up picture please?

Theses are is a closes up of the seam.

It's not a bad seam, however, the saw blade "bruised" the stone as it cut. Your installer should have run a color matched Sharpie down the top of the seam sides before gluing with a better color matched adhesive. Try it now anyway please.

Perfect. Thanks so much!