The simple answer is "no", it is not "normal" in the sense that most or even a large minority of adult women feel the same.
However, I think you may want to ask a different question, which is: is a woman enjoying messing her pants harmful or wrong?
The answer to that is "it depends". If the woman does it only in private and without guilt, then it falls into the category of a strange but harmless fetish. It does no harm to anyone else nor, apart from some extra laundry bills, the lady herself. However, if she is obsessed with doing this in public where strangers might see, it is a problem that needs counselling. Similarly, if the woman has guilt feelings about what she is doing, it would be well to seek help to determine how to manage those feelings in the future.