Kids' profiles no longer allow any access to the internet, unless I disable Parental Controls

About 2 weeks ago, the two user profiles I have for each of my kids are no longer allowing any access to the internet through Safari or Chrome. I use Parental Controls to limit time and access to adult websites. My login is able to access the internet without any program.

I'm on a 2017 21.5 inch iMac, 3 Ghz Intel Core i5 with 8 GB RAM. I'm currently running macOS version 10.13.6.

Troubleshooting completed:

• Checked Network settings in Preferences - all the same as my profile
• Changed Parental Control settings, allowing all websites instead of adding restrictions - no change
• Disabled Parental Control settings completely - now Internet Access is available on Safari
• Re-enable Parental Control settings - Internet access is no longer available on Safari

Clearly, there's a glitch within Parental Control settings that causing the problem. I've only found a couple of questions on forums from 10 years ago, but they didn't help. Anyone know how I can resolve this?

Thank you!