after firmware flashing the ble work for some time in few board (Bluetooth is not working when it go into market )

1.programming a FW code to nRF51 Development board everything is working . but the same programming in custom board every 10 out off 50 board are not working.these board work once a while by touching the board some where to the ground .

2. is this hardware issue or any thing else please check the attached schematic and layout?

Please help regarding this issue .due to this issue we have facing so many business loss