Will one be rewarded for fasting a day of make-up if the fasting person breaks their fast in response to Imam al-Sadiq's invitation?

It is not permissible for one who is fasting to make up for Ramadan (definition) (qaḍāʾ) to break their fast unless there is an excuse that permits breaking the fast during Ramadan. This is by scholarly consensus. As for a voluntary fast (nafl), the fasting person is their own master, and it is permissible for them to break their fast if invited to a meal. They have the choice between breaking the fast and continuing to fast, while supplicating for the host. What is mentioned about Jaʿfar al-Ṣādiq concerning breaking the fast—its authenticity is unknown, and it is not thought that he intended obligatory fasting.