Child's screen time keeps turning off

I am the organizer of my family and using my phone, I turn on screen time for my 14 year old child. However, it turns off automatically. Sometimes in one day sometimes in less than a day, there is no particular event I can identify. I have tried now for months but the same thing keeps happening. I know that my child is not doing it because I have kept her phone with me and it still turns off. My phones and laptops are all updated and on the latest iOS/macOS versions. Getting screen time to work reliable is critical. There isn't much help on this online. Can someone from apple respond as to what might be going on?