Sound concrete floor was primed and then flexible tile adhesive laid before putting down XPS insulation boards. Underfloor heating was put down on top of this. Then self leveling compound. Self leveling compound now has very fine cracks over it, thinner than a hair. Some sound hollow but not all. Also it appears that some of the underfloor heating mat has raised. Large 60x60 porcelain tiles are to be laid on this this. Will these cracks cause problems ?