I uploaded a GEDCOM file with a residence fact applied to a married couple (but not their children) and gave 3 census records as supporting evidence. The residence fact has a date of “from 1909”, which is when the couple was married. Upon upload, RootsFinder applied the fact and the sources to all children in the family, so they all end up with a residence fact starting (“from 1909”) before they were born.
I finally figured out how to fix this, by removing all the children from the 3 census records.
In another case, I had a residence fact for a couple that was after their children were born and my GEDCOM file already had residence facts for their children. The upload generated duplicate residence facts for the children - that is, it used the couple’s residence fact to generate a new fact for each child, even though there already was a residence fact for the child with the same year and place.
I don’t think that residence facts should be automatically assigned to the children, since you can’t guarantee that they live with their parents up to any particular age. If you are going to generate them, though, you have to ensure that the dates are within the lifetime of the children, and that they are not duplicates (or overlapping) with residence facts already assigned to the child. I would just refrain from creating them - feels a bit “too clever”. Or maybe make it an option.