Approved Ask to Buy apps downloading on all child devices

Recently when one of my children uses Ask to Buy to get free Apps when approved it downloads on both of their devices, it also downloads on the other child's device even though they are signed into the store using the parent account. I have checked that auto-download purchases are not turned on.

Any other ideas? I can possible understand apps downloading on both devices for the same account but not on the other child's account that is using the parent account for purchases. Apps arent downloading on any of the parent's devices.