There shouldn't be any bugs with the NFC examples in our SDK. Your board looks very small to fit a good NFC antenna on. Did you follow the NFC Antenna Tuning instructions provided by Nordic Semiconductor when tuning your antenna?
Have you calculated the inductance, or been able to measure it? If not I recommend you do that. You should also check that your capacitors C16 and C19 are correct so that the NFC antenna resonates at 13,56 MHz
Lastly check that the NFC pins are enabled as the UICR suggests.
Best regards,
Simon
EDIT: If you have a development kit available you could test the example code with that to make sure your phone (and the code) is not the problem.
