Is there any prohibition for qaza namaz between sunnat and fardh namaz in Fajr or is it sinful?
بسم الله الرحمن الرحيم
(Fatwa: 1165/993/SD=9/1439)
It is not forbidden to offer qaza salah between the sunnah and fardh salah of Fajr rather it is lawful.
Allah knows Best!
Darul Ifta,
Darul Uloom Deoband