How do I fix unpredictable Downtime turning on and off on my son's iPhone?

On an iPhone, most system behaviors are triggered by a specific event, setting, or automation rather than occurring randomly. If you're experiencing unexpected activations or deactivations of Downtime, consider these possible triggers:

1. Shortcuts Automation – Check if you have a Shortcut that enables or disables Downtime. Go to:
   1. Shortcuts app > Automation
   2. Look for any automations related to Downtime and see if one is running unexpectedly.
2. Screen Time Schedule – If Downtime is turning on/off at certain times, check if you have a schedule set:
   1. Settings > Screen Time > Downtime
3. Focus Modes – Some Focus modes (e.g., Sleep or Work) might activate Downtime when turned on.
   1. Settings > Focus
   2. Check if any Focus modes have Downtime enabled.
4. Family Sharing & Parental Controls – If you’re part of a Family Sharing group, a parent/guardian may have control over your Downtime settings.
5. Third-Party Apps – Some apps (especially parental control or productivity apps) might be managing Downtime.

This may help --> Parental Controls through Screen Time for… - Apple Community