Mishkat al-Masabih 2015
Abu Sa'id al-Khudri reported God’s messenger as saying, “Three things do not break the fast of one who is fasting:
cupping, vomiting, and a nocturnal emission.” 

Tirmidhi transmitted it saying this is a tradition which is not regarded, its transmitter ‘Abd ar-Rahman b. Zaid being declared a weak traditionist.
عَنْ أَبِي سَعِيدٍ قَالَ: قَالَ رَسُولُ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ: «ثَلَاثٌ لَا يُفْطِرْنَ الصَّائِمَ الْحِجَامَةُ وَالْقَيْءُ وَالِاحْتِلَامُ» . رَوَاهُ التِّرْمِذِيُّ وَقَالَ: هَذَا حَدِيثٌ غَيْرُ مَحْفُوظٍ وَعَبْدُ الرَّحْمَنِ بْنُ زيد الرَّاوِي يضعف فِي الحَدِيث