What are these "lines" on the A319 flaps, are they damaged? I've noticed a grey line on the flaps of the A319:  



What is that?
Source
You are seeing the steel reinforcing sheet metal at the line where the spoilers rest on the flaps when both are retracted.  It is there as a bearing surface since there is some inevitable contact between the spoilers and the top surface of the flap when they are both retracted during flight.