safrus - Understanding places where the Torah writes היא instead of הוא

In most cases in the Torah, the feminine 2nd person word (equiv. to "she" or "her" in English) is written as הוא using a ו and pronounced הִוא .

Avot Derabbi Natan 42:5 lists 11 places in the Torah where the word is written as היא with a yod. (Of notable interest is the 2nd verse that combines writing the word both with a vav, with a yod and the form with a vav used in the masculine form.)

Is there a reason why these situations are made the exceptions? Does anyone discuss a hidden meaning (Midrash, etc.) as to why this happens?