The program only can go by what you enter. I am not sure why you weren't able to claim your son since you claimed him in 2018. Since you already filed a 2019 return without your son, & if the IRS fully processes your 2019 return, you would not get the stimulus money for your son because he was not on your 2019 return. When you file a 2019 return & it gets fully processed, the IRS use the information from the 2019 to qualify for the stimulus money.
