What is the ruling on the fast of a woman who fasted Ashura while she was menstruating, having forgotten her menstruation, and will she be rewarded for it?

"This woman who fasted on the Day of Ashura while menstruating—her fast is not valid by scholarly consensus. Fasting in this state is not considered to have taken place, nor does it earn reward; it is as if it never happened. No text from the jurists has been found regarding her receiving reward for her intention, but the grace of Allah is vast."