It can't be left the way it is. You may be able to put a surface patch over the screws.
That contouring around the end of the curb doesn't look like the right material, either. And why does the curb appear to slope downwards at the wall?
Has this contractor ever worked on something like this before?

Is this an outdoor shower?

At first I assumed that the screw was accidental. But they obviously are intentional. Is this a plumber or a tile contractor?
In any event, I would be inclined to tell them never to come back to my premises.

The screw hole is easly repaired but I would leave the repair up to the tile installer. In the future,have wallboard and pan linner installed by tile contractor. G.C.s often have drywallers do the inclosure since they are cheaper and thereby increase's his profit.

Thanks everyone for the advice! We had him re-do it with a new liner, and are flood testing right now. A little disturbed that we had to explain to him that it was a code violation....

" "A little disturbed that we had to explain to him that it was a code violation...."

Understatment at best.