Have you tried contacting the stone supplier/manufacturer?

clearly not from the same lot, one had some finish that the other didnt. but anyway the store where you purchased it from needs to enter the loop.

the box must have been 2 lots combined somewhere along the way.

Maybe the lighter pieces just need to be sealed? Hopefully.

Most things like that have some variation which is why you always want to open multiple boxes so you can intersperse them together to avoid what happened to you.

I wouldn't be surprised if they were from the same lot, and the variation is normal. We just laid hardwood in our living room last week, and were amazed at the variations in color between boxes of the same lot. Some was very white, some red and some brown. Once we mixed them together, it looks like a normal hardwood floor with the variations in color.

Unfortunately it is up to the installer to catch this prior to installation. More than likely the distributor will not pay for replacement. It will come out of the customers or contractors pocket.

I contacted the manufacturer and they said to call Lowes and issue a claim again Dal Tile for the Tile and install. So even if it's the same tile maybe the manufacturer mixed the lots or didn't treat the tile the same way? Contractor bought 2 boxes at the same time with the same lot number.

either the manufacturer mixed lots in the box or someone returned them this way.

You bought the material from Lowes? Was it something they had in stock or did they order it in?

OP says it looked fine before grouting, which means perhaps one of the kinds had more water incursion than the other, or something.

I would suspect the problem would fall on lowes if they filled the order since it was stocked at their location(unless you picked through a pallet). Dal Tile is not at fault and will most likely state that installation of the product shows acceptance.