Hello, kristiryczek,
Thanks for using Apple Support Communities, it's great to have you here.
Being able to customize your child's device access is really important and we want to help you get this sorted out. From here, we want to recommend that you ensure that all of the devices in use here are up to date on the latest version of iOS, iPadOS or macOS. Updating your device is an important first step in resolving many types of issues, so it's definitely worth starting with. You can follow these steps to update: Update your iPhone or iPad - Apple Support
If the issue continues to occur after that, the best option would be reaching out to Apple directly. This will enable you to work with an advisor over the phone, one on one, to troubleshoot this issue further. You can head here for that: Apple Support
We hope that this information is helpful.
Have a great day!