أحسن الله اليكم Ustadh, in Qawai'd Al Muthlah, Imam رحمه الله mentioned that the legal punishment is not to be carried out when they repent before it, as in Surah Al-Ma'idah Ayah 34. However, from the sunnah that someone repented and حد was carried out. Was it because they asked for حد themselves?

Ustadh AbdulAziz al-Haqqan

Yes