They make different copper pipes. You are supposed to use the thicker type L for underground, slabs etc. I bet you have type M or ???l under the sab. It is less expensive and the builder will be long gone before it fails.
Also if they use calcium chloride in your cement to make it set up faster, I have heard that it makes the concrete more corrosive. I may have to research that.
The reinforcing grid in you slab should be grounded, if stray ground currents are not properly controlled, then electrolysis can erode the pipe too. I put in an outside freezeproof water hydrant and electrolysis ate a hole in the pipe in less than 10 years. It was the same day ad Dad passed away. I was out there digging a hole, bet Dad was looking down and smiling. He did teach me well. When I put it back, I connected copper ground wire to the pipe, ran it another couple of feet away and put in a magnesium anode (chunk of a scrapped lawnboy mower deck) That was a $780 dollar water bill and a lot of mudding around.
One of the contractors that built in my current neighborhood even used schedule 40 plastic pipe for the water service entrance, now they are breaking and the homeowner is shelling out a thousand or more to dig up and replace properly with schedule 80 bedded in river gravel (we have rocky Ozark soil). That had to save the contractor all of $100 including the gravel.
Rod