How do I prevent a child adjusting their time zone to avoid parental control?

For some reason, changing the time settings is disabled for one of my children (iPad Air 4 with ios 26.2.1) but not for the other child (iphone 12 mini with ios 26.0.1). This allows that child to change the time such that screentime limits are not enforced*.

Within family screentime settings, I cannot find any option to block changing time. I tried finding a solution in earlier community posts but the settings seem to have changed since then.