Grouting Natural Stones
Did you follow the Schulter directions to the ,"T"? What sort of thinset did you use? Did you set the drain into thinset? Not the collar, but the plastic insert?
I did a Schulter system for a customer and found if I didn't set the drain insert into thinset, it would push down when you stood on it. Since this is a weekend house 130 miles from home, I stay here during the week to work. I've been using this shower for a few months and haven't experienced any issue with the tile around the drain.