Downtime not working on childs phone

This is a very frustrating issue. My child's iphone is still on when downtime should be on. Ive checked all settings on my controls, checked blocked at end of limit is on for all apps, even reduced time on all apps to 1 minute. I’ve checked downtime settings are all correct and enabled. Please do not tell me how to do all these settings, she has had the iphone 15 for a while. These restrictions used to work but now don’t. It seems to be a bug that needs fixing. Please help. Both our phones are running latest software.