I completed the Benedict questline, including the Rescue Children from Penitents mission in Eta Ceti. Later, in the Li system, I got a mission from a Ferian Colony to destroy a different Penitent Monastery. After destroying this monastery, I docked with it and got the dead children dockscreen.
It makes sense there are children in other monasteries, but I think this may be a bug. I docked with the monastery both before and after getting the reward from the ferian colony, and got the same dialogue.