There has been a lot of research on tea fluorine, especially tea made with older leaves consumed by northwest regions of China. Most of the studies show that the older the leaves, the more fluorine there is. Traditionally, these very old leaves are made into mostly hei cha and low grade puerh. But in the traditional time, such tea with fluorine helped northwestern nomads people get enough nutrients and minerals. It was a trade-off between extra fluorine and additional nutrients, because traditional nomads people had mainly meat and dairy diet and tea, especially rough tea, was very much needed.
Most of those tea fluorine studies also suggest that, as long as the tea leaves are not extremely old or low grade - still talking about relatively low grade leaves in hei cha, and just not extremely low grade - fluorine wouldn't be a problem. So, either the woman drank too much tea, or her tons of teabags had mysterious sources
Besides, one case without repetition never says much about anything. I bet there are people who never touch tea get fluorine problems too