Travertine tile deck and grout issue..

I am Remodeling my pool. I had aggregate concrete for the decking. They extended the pool deck some as well. Total is about 550 sqft.
They laid down Travertine tile over top. I picked a very similar grout color to the travertine tile. They laid the wrong grout the first time. They came back and cut out every grout line and laid the correct grout. But the color has changed. It went from a Sandy beige color to a white. Some areas it stayed the same. The grout color is not consistent.
On the...

Travertine tile deck and grout issue..