What's the issue about
VPN on the child device from the junior is being disconnected. This issue would affect the content filtering, pause internet, and time limit on the child device as the VPN is used for blocking websites and other content on the child’s device. VPN is also used for the correct functioning of the screentime feature.
How to solve it
On iOS, the issue is usually caused by another VPN being used on the device.
To find out if there is a different VPN used on the device that is causing the Family Security child app to be disconnected check if the VPN settings show only the Junior App in the list of VPNs:
Settings > General > VPN
If there is another VPN app on the device then suggest uninstalling it and removing the profile.