Another point of attention is moisture or water. If the slab is soaked with water the adhesive will not adhere to the surface.
Due to the occurring stress on the surface at the moment of application of the glue bead, a water film will occur between the natural stone slab and the glue bead which ultimately will block the adhesion of the adhesive bead on the natural stone (please have a look at this).
The advice is therefore to store the natural stone on a dry place (not in the rain) in order to make it possible to dry the natural stone slabs and thus to achieve a problem-free glued connection.
Of course this item is not applicable on natural stone only! It matters on all cladding material!