Question and Answer:
Q. I have some Qadha fasts to keep for the previous Ramadaan due to previous pregnancies. I wanted to know if its ok to keep Shawwaal Nafl fasts. Will it be valid even though I have outstanding qaza fasts?
(Query published as received)
A. Due to the Qadha fasts being Fardh, they hold priority over the Nafl fasts and you should try to give due importance to your Qadha fasts. However, this does not mean that you are not permitted to keep any Nafl fasts at all. It will still be permissible for you to keep Nafl fasts and you will attain the rewards of these fasts. However a concerted effort must be made to complete your Qadha fasts. (Adapted from Raddul Muhtar).
And Allah Knows Best