Fathwa, - Incipience of menstruation whilefasting

Question:
In the sister's halaqa I go to we had a disagreement on what to do if
a woman starts menstruating while fasting. We agreed the fast was
broken and must be made up, but some said if it happened after 10 am
than you have to still act like you are fasting and not eat anything
until iftar time. Is this true or is it culture?
Answer:
Assalamu alaykum
In the name of Allah the Inspirer or truth.
A woman does not have to act like she is fasting for the rest of the
day if her fast is invalidated by the coming on of menstruation. There
is a light disagreement among the jurists as to whether she has to act
like a fasting person on this day [See Radd al-Muhatar 1:193] but no
mention or distinction made on the basis of the time the menstruation
begins.
However, she does act as a fasting person for the rest of the day
until iftar on the day her menstruation ends (al-Durr al-Mukhtar
2:106)
And Allah knows best.
Wassalam