Wireguard - Dnsmasq

[Javier®]

Hello everyone, I'm trying to configure WireGuard using the IPv6 prefix I received to avoid NAT for IPv6 traffic. I created a WireGuard instance with the assigned prefix and a unique IP address, and automatically, in the Dnsmasq leases, the connected devices switch from LAN to VPN (strange).
VPN is the name of the WireGuard interface.

You cannot view this attachment.

You cannot view this attachment.

You cannot view this attachment.  <--- From LAN to VPN

What am I doing wrong?

Thanks

If it is relevant, I only request the prefix and size.
And manually I configure prefix ID, interface ID

You cannot view this attachment.