@Max You can do a test. Make a backup of your current configuration if you haven’t already.
Make sure parental control is enabled. Then unplug the power. Power up the router again. Login to check the status of parental control. Is there any change?
If parental control is disabled after rebooting, reset the router. Then do the initial setup. Then restore your backup. After restoration, repeat the test. Configuration should not change after rebooting.
BTW, what is the firmware version?