The Messenger of Allah ﷺ would wake up in the morning in a state of major ritual impurity, not from a wet dream, and then he would fast.Along with this hadith, she also reported that she once brought the Prophet ﷺ a roasted side of meat. He ate from it, then got up to pray without performing ablution.
أخبرنا محمد بن عبد الأعلى قال حدثنا خالد قال حدثنا ابن جريج عن محمد بن يوسف عن سليمان بن يسار قال دخلت على
أن رسول الله ﷺ كان يصبح جنبا من غير احتلام ثم يصوم وحدثنا مع هذا الحديث أنها حدثته أنها قربت إلى النبي ﷺ جنبا مشويا فأكل منه ثم قام إلى الصلاة ولم يتوضأ
Muslim narrated it in "Fasting," in the chapter on the soundness of the fast of one who wakes at Fajr in a state of ritual impurity, hadith no. 1109, from the hadith of Ibn Jurayj, with the same chain. It is also found in Kubra, hadith no. 189.