Wireguard init script auto-route creation issue

I have wireguard encrypting the connection between two private LANs -- nothing exposed to the WAN interface. However, they are on different private IP networks and during wg init a route will be created for the target IP that has the WAN IP as the gateway. They connect fine when I delete that route (and I have a hotplug script that will do just that) but it seems that this shouldn't be getting created in the first place. Example:

config interface 'wg0'
    option proto 'wireguard'
    list addresses ''

config wireguard_wg0
    option endpoint_host ''

When wg starts up a route is created like this:    <wan-ip-gateway>   <wan-interface>

I believe the section doing this is:

  wg show "${config}" endpoints | \
    sed -E 's/\[?([0-9.:a-f]+)\]?:([0-9]+)/\1 \2/' | \
    while IFS=$'\t ' read -r key address port; do
    [ -n "${port}" ] || continue
    proto_add_host_dependency "${config}" "${address}"

Eyeballing the netifd helper script an interface can be added to the proto_add_host_dependency call but I haven't really thought through how this should be done while keeping the implementation generic. I'm guessing the difference in IPs is noted but surely a private IP should never be routed to a gateway on the WAN interface?