Internet block devices - parental control not working


I'm running OpenWrt 21.02.3 r16554-1d4dea6d4f on my Xiaomi R3P.

I have some cameras and I want to keep them on LAN only.

So I have tried parental control : Add IPs, block theme any day, any hour.

But they still have internet !
I have launch the "reorder firewall rules" script, same.

I don't want to create a "iot zone" because all is configured with the same network IP right now.

Thank you for your help

set them up with static IPs, skip the DNS and default GW, or provide bogus IPs.

or do the same, by using the DHCP.