Hello All, Hope all is well

I have a client I sealed a slate floor for (with enhancer) about two years ago,  she sent me an email asking this, Any help is appreciated.

SHE WRITES:

I have an odd issue with my slate floor in my kitchen. There is a large white marks on it. It's a small area by the dishwasher. I tried to clean it myself and as soon as it dries it re appears?!

I ask about any hot pots sitting there or a mini water damage, maybe a little puddle of water that didn’t get wiped up and went into the slate.

 She replied with this.

no nothing-it's odd-looks like maybe some how it was the detergent form the diswasher...maybe Tony did it and doesn't want to say??? It looks like wipe up strokes etc.

I’m thinking someone wipe the slate with a strong acid.

Any thoughts on this?

If its an etch can slate be polished then enhanced again?

Thanks
Randy
Cleaning Edge
Naples, FL