Well it still didn't change the fact that the President's Father is Indian and therefore her race in her NRIC is Indian and the dual race identification is only applicable to those born after 2011. So other than you telling us that the President was born in 2011 and was 6 years old when she contested for the Presidential Election, the dual-race thing does not apply to her.

In Singapore you follow the race of your father by default. So if your Father's race in the Identification Card is Indian, your Identification Card will identify you as an Indian. Only recently after the election are you allowed to add your mixed heritage such as Indian-Malay, Malay-Indian and etc to your Identification Card. For the most part the first race is usually of the Father's race followed by the Mother's race as declared in the Identification Card.