It could very easily be nothing wrong with the phone and it is not defective but something wrong with the users.
The problem is OP skin could be more acidic than the normal population and as such eats away at the covering faster than it should normally. For example my girlfriend has very acidic skin and will pit jewelry very quickly and I am not talking about cheap jewelry but 18k gold stuff will get pitted in a matter of month or 2 where it touches her screen. The stainless steel watch I got her for Christmas already has pits in it.
It nothing wrong with the phone but at the same time it failed under normal use so chances are they will warranty replace it.
The problem is OP skin could be more acidic than the normal population and as such eats away at the covering faster than it should normally. For example my girlfriend has very acidic skin and will pit jewelry very quickly and I am not talking about cheap jewelry but 18k gold stuff will get pitted in a matter of month or 2 where it touches her screen. The stainless steel watch I got her for Christmas already has pits in it.
It nothing wrong with the phone but at the same time it failed under normal use so chances are they will warranty replace it.