Is it permissible to perform a voluntary prayer after combining Dhuhr and Asr prayers and after performing the Sunnah prayer of Dhuhr in Al-Aqsa Mosque, and before the Adhan of Asr?

It is forbidden to voluntarily perform a supererogatory prayer (nafilah mutlaqah) after combining the Dhuhr and Asr prayers with an early combination (jam' taqdim). The term "nafilah mutlaqah" refers to any non-regular supererogatory prayer. The jurists have agreed that it is not permissible to perform supererogatory prayers after the Asr prayer until sunset, and this includes the Asr prayer that was performed with an early combination.