Vitamin D & breastfeeding

Is it true that a breastfed baby can not absorb too much vitamin D even if the mother is taking supplements because of deficiency?

The vitamin D upper limit (UL) for lactating women is 4000 IU so as long as you’re not going above that much you and your baby should be fine. You should be getting at least 600 IU of vitamin D each day. (These are Canadian guidelines, by the way)

As far as I know there aren’t any documented cases of healthy people (but not those suffering from primary hyperparathyroidism, sarcoidosis, tuberculosis, and lymphoma - wiki) suffering vitamin D toxicity at levels less than 40,000 IU daily for months <–this is the number for babies, ftr.