When they are adults, they will get run on our instrument (NEO) that picks up most weak D reactions, so they stay Rh pos. If not, we will change their type and put a comment regarding testing methods and why the change.
We have the same type issue when prenatals are done at outside labs that perform weak D (+) and then the moms come here to deliver and we don't (=). Or a weak D blood donor (+) becomes a patient (=). We just explain the discrepancy to the physician, call them Rh neg and offer them RhIg, if indicated.
I used to work in a facility that also collected autologous blood. We were required to weak D donors units, but not patients, so sometimes that got really confusing when their blood type per blood bank is Rh=, but their unit is labeled Rh+.