This is directly from the Jamaican Constitution. PDF available here...https://www.constituteproject.org/constitution/Jamaica_2011.pdf. Note the first clause of section 3C.
3C. Citizenship by descent
Every person born outside Jamaica shall become a citizen of Jamaica. on the sixth day of August, 1962, in the case of a person born before that
date; or
b. on the date of his birth, in the case of a person born on or after the sixth day
of August, 1962,
if, at that date, his father or mother is a citizen of Jamaica by birth, descent or
registration by virtue of marriage to a citizen of Jamaica.
Frank,
Thanks again for finding this!
(She is subject to more than one nation’s laws because she possesses multiple citizenships.)