Screen Time restrictions not working on my child's iPad

I have turned on App Limits for my daughter and recently she received an iPad as secondary device at school. The is logged-in the both devices with her Apple ID. Taking a look at the App and Website activity I see reports that are way above the defined limits that I have configured as linked parent.

I checked all settings but either do not understand the restrictions or restrictions are not applied. Some examples:

• We have configured in "Screen Limits" section "All Apps & Categories" a limit of 1:30h on every day
• But I see that on one day she consumed screen time of 8:25h on both devices in sum. (5h iPad and 3:25 iPhone) - Can usage only restricted per App - I understood the limits are global for all Apps.
• The usage report shows that Safari was used on her iPad in sum 2:50h - why is Safari not included in "All Apps"? (That makes it rediculous to restrict Apps if the browser is the "open door" to just continue)
• Report shows she was using Instagram on the same day 1:48h - how is this possible if the limit is 1:30h? (Note: The time was reported only on one device, iPhone, no usage on the other device)
• Report shows she was using Youtube on the same day 1:39h - how is this possible if the limit is 1:30h? (Note: The time was reported only on one device, iPad, no usage on the other device)
• When I want to restrict "Safari" I can not select this separate because in the list of Apps Safari is not listed. How can this be configured separately?
• Individually I see that for my personal (parent) screen time I can select "Share Across Devices" but as parent I am not able to apply this to the settings of my Daughter. Besides that limits are exceeded it seems the limits are not shared across her devices? Can I influence this?

Technical Details:

• My daughter is age 15 and listed in my family account correctly
• iOS 18.4.1 (across all devices (parent, childs iPhone+iPad)

[Re-Titled by Moderator]