I see what you mean now, it wasn't the type of haze that i thought, as in grout haze residue.
It looks like it has deffo lightened but hard to tell from the pic if it is a residue of sorts , i would contact the sealer supplier/manufacturer and ask if the sealer can effect the stone in anyway..
That brand is not one i have used or know about , so can not comment on usage... i would not say it has bloomed as after that time scale the stone should have been dry.?
Andrew above has posted a link to guys who use that product, so maybe they can offer a solution to what has happened.