Miley Jab Hum Tum S12 E13 Gunjan Sings in Gurgaon

At the Gurgaon bus stand, Mayank asks Gunjan to sing Nupur's favourite song so that she comes to them. Gunjan starts singing and soon Nupur finds them. Gunjan breaks down and hugs Nupur, but all are shocked that Nupur doesn't respond. Why is Nupur refusing to recognize them?