Reference: Fataawa Ramadhaan – Volume 2, Page 547, Fatwa No. 529
Fataawa as-Siyaam libni Jibreen – Page 48
Question: If one who is fasting does that which is not permissible for one who is fasting, does it ruin his fast and does he have to refrain from all that which breaks the fast for the rest of the day?
Response: Anyone who does an act that breaks the fast, then we say his fast has been nullified for that day. However, it is upon him to refrain from all else that breaks the fast for the rest of the day, out of respect for this blessed month. Then he must make up this fast.