Parental control screen time settings get lost after a few days on my son's iPad

Hello community,

I have an issue with screen time settings under parental control which seem to get lost after a few days. I set the screen time settings on my iPad Mini for my son's iPad Mini. My iPad is connected to the Internet/Cloud roughly only once per week (per WiFi), the rest of the time I use it offline. Now, after a few days, the settings for screen time for my son's iPad get lost, and he can use it without any limits :( My son's iPad is connected more frequently to the Internet.

Could it be that the settings get discarded if the parent's iPad has not been online? If yes, does anybody know what the delay would be?

Thanks in advance!

Claude