Answer
(Fatwa: 600/600=M/1429)
We have not read any Hadith which says that there is no Sajdah after Asar and Fajar. If you gave the reference, we would write some thing about it. However, there is another Hadith in Sahih Bukhari and Sahih Muslim:
لا صلاة بعد العصرحتى تغرب الشمس ولا صلاة بعد الفجرحتى تطلع الشمس
i.e. there is no salah after Asar till the sunset and after Fajr till the sunrise.
Here salah means nawafil (nafl salah), thus the Hadith means: there is no nafl salah after obligatory salah of Asr and Fajr, however performing qaza is permissible. You can offer qaza salah after Asr and Fajr:
لايكره قضاء فائتة بعد طلوع فجر سوى السنة الخ (الدر المختار)
Allah (Subhana Wa Ta’ala) knows Best
Darul Ifta,
Darul Uloom Deoband