The name is anachronistic, and no Banu Qasi is attested until Mutarrif ibn Musa during the 780s, but he is identified with just his father's name and not explicitly linked to Cassius or the Banu Qasi.
The name seems out of place historically, as there is no record of a Banu Qasi named Cassius until Mutarrif ibn Musa in the 780s, but he is only recognized by his paternal surname without any explicit association with Cassius or the Banu Qasi.