Does being unaware of the prohibition invalidate the fast when performing an action that breaks it?
General Chapter
Al-Mughni
Book of Fasting
Primary text
If one performs an act that typically breaks the fast while asleep, the fast is not invalidated because there is no intention or awareness of the fast, making the sleeper more excused than one who forgets. If one performs a nullifying act while being ignorant of its prohibition, the fast is not invalidated, according to Abu al-Khattab's mention; however, this view is not strongly attributed elsewhere.
Supporting text
The statement of the Prophet, peace be upon him, 'The cupper and the one being cupped have broken their fast,' regarding two men who were ignorant of the prohibition, indicates that ignorance is not an excuse for breaking the fast. This is analogous to the ignorance of the time of dawn, where one eats thinking dawn has not arrived when it has.