SHAFAQNA – The Grand Ayatollah Khamenei answered a question about fasting and the limit of distance for a journey before breaking fast.
Question: If a person who is fasting is unaware that he/she has not travelled enough to reach the limit which is required to break the fast before sunset; and breaks his/her fast before that limit by thinking that he/she is considered as a traveller; what is the ruling about such a person? Is it Wajib for him/her to compensate for missed fasting days (Qadha), or some other ruling applies?
The Grand Ayatollah Khamenei: Based on the supposition in the question, his/her fast is void (Batel), and must compensate for the lost days of fasting (Qadha), but if was unaware of the ruling, there is no need for Kaffarah.
Source: PERSIAN SHAFAQNA