When Rukhsana jumps off balcony to feed herself, length of her trousers (kurta) is different between shots.
After Arnab Bagchi's car runs over a woman and he steps out of the car, though its supposedly raining heavily, you can clearly see its bright and sunny in the distant background. Fatal editing error.
Various police personnel are shown in khakis. West Bengal police wear white uniform.
The time displayed on CCTV when Kanai is monitoring during his duty at night and when Professor is reviewing later are different.