ayat of rajm being eaten by an animal is also in musnad of imam Ahmed. however, one particular instance does not mean that it was lost forever, no, we have the abrogated ayah of rajm in other hadith books and tafasir. there were others amongst sahaba who had saved it. ironically, all shia commentators such as tabrasi and tusi quote it and report the ayat e rajm in their tafasir. it was abrogated in recitation but remains in hukm.