OpenWrt LAN devices showing WAN6 IPv6 address on IPv6 test website

Hello,

I'm using OpenWrt as my home router and I've noticed an issue. When I access http://ip.sb/ or https://whatismyipaddress.com/ from a device on the LAN side (e.g., my computer or phone), the IPv6 address that is shown is the one from my router's WAN6 interface.

I would like these devices to display their own assigned IPv6 addresses instead, to get a more accurate understanding of each device's network status.

Is there a way to accomplish this? Thank you very much!