OSPF wireguard fallback

[chrono]

Ahoy all,

I'm struggling a little to set wireguard as a fallback link
in conjunction with two MPLS links. In my tests BIRD would
not route traffic through wg0 when I took the other two
interfaces down. The setup is rather simple, two DCs, each
side has a gw running BIRD.
---- Config DC1 ----

router id 192.168.184.1;

### Kernel 
#####################################################################

protocol kernel {
  scan time 15;       # Scan kernel routing table every 15 seconds
  export all;         # Default is export none
}

### Device Monitor 
#############################################################

protocol device {
  scan time 10;       # Scan interfaces every 10 seconds
}

### OSPF 
#######################################################################

protocol ospf MyOSPF {
  tick 2;
  ecmp yes;
  rfc1583compat yes;

  area 0.0.0.0 {

    # Advertise DC1 prod net
    stubnet 192.168.184.0/24;

    # MPLS1 interface
    interface "macsec.2335" {
      cost 5;
      ecmp weight 1;
      bfd yes;
      authentication cryptographic;
      password "testtesttest" {
        id 1;
        algorithm hmac sha256;
      };
    };

    # MPLS2 interface
    interface "macsec.2334" {
      cost 5;
      ecmp weight 1;
      bfd yes;
      authentication cryptographic;
      password "testtesttest" {
        id 2;
        algorithm hmac sha256;
      };
    };

    # WireGuard Fallback
    interface "wg0" {
      cost 10;
      bfd yes;
      type pointopoint;
      authentication cryptographic;
      password "testtesttest" {
        id 3;
        algorithm hmac sha256;
      };
    };

  };
};

### BFD 
########################################################################

protocol bfd PCrewBFD {

  # BFD on DTAG interface
  interface "macsec.2335" {
    min rx interval 20 ms;
    min tx interval 50 ms;
    idle tx interval 300 ms;
  };

  # BFD on Console-Networks interface
  interface "macsec.2334" {
    min rx interval 20 ms;
    min tx interval 50 ms;
    idle tx interval 300 ms;
  };

  # BFD on WireGuard interface
  interface "wg0" {
    min rx interval 200 ms;
    min tx interval 500 ms;
    idle tx interval 3000 ms;
  };


  # WTF is multihop??
  multihop {
    interval 200 ms;
    multiplier 10;
  };

};


---- Config DC2 ----


router id 192.168.148.1;

### Kernel 
#####################################################################

protocol kernel {
  scan time 15;       # Scan kernel routing table every 20 seconds
  export all;         # Default is export none
}

### Device Monitor 
#############################################################

protocol device {
  scan time 10;       # Scan interfaces every 10 seconds
}

### OSPF 
#######################################################################

protocol ospf MyOSPF {
  tick 2;
  ecmp yes;
  rfc1583compat yes;

  area 0.0.0.0 {

    # Advertise MUC prod net
    stubnet 192.168.148.0/24;

    # MPLS1 interface
    interface "macsec.2335" {
      cost 5;
      ecmp weight 1;
      bfd yes;
      authentication cryptographic;
      password "testtesttest" {
        id 1;
        algorithm hmac sha256;
      };
    };

    # MPLS2 interface
    interface "macsec.2334" {
      cost 5;
      ecmp weight 1;
      bfd yes;
      authentication cryptographic;
      password "testtesttest" {
        id 2;
        algorithm hmac sha256;
      };
    };

    # WireGuard Fallback
    interface "wg0" {
      cost 10;
      bfd yes;
      type pointopoint;
      authentication cryptographic;
      password "testtesttest" {
        id 3;
        algorithm hmac sha256;
      };
    };

  };
};


---- BIRD states ----

bird> show route

172.23.1.0/29      dev macsec.2335 [MyOSPF 09:26:22] * I (150/5) 
[192.168.184.1]
172.23.2.0/29      dev macsec.2334 [MyOSPF 09:26:22] * I (150/5) 
[192.168.184.1]
192.168.148.0/24   multipath [MyOSPF 09:27:26] * I (150/15) 
[192.168.148.1]
        via 172.23.1.2 on macsec.2335 weight 1
        via 172.23.2.2 on macsec.2334 weight 1
172.23.3.0/29      dev wg0 [MyOSPF 09:26:22] * I (150/10) 
[192.168.184.1]

bird> show ospf state all

area 0.0.0.0

        router 192.168.148.1
                distance 5
                network 172.23.2.0/29 metric 5
                network 172.23.1.0/29 metric 5
                stubnet 172.23.3.0/29 metric 10
                stubnet 192.168.148.0/24 metric 10

        router 192.168.164.1
                distance 0
                network 172.23.2.0/29 metric 5
                network 172.23.1.0/29 metric 5
                stubnet 172.23.3.0/29 metric 10
                stubnet 192.168.184.0/24 metric 10

        network 172.23.1.0/29
                dr 192.168.164.1
                distance 5
                router 192.168.184.1
                router 192.168.148.1

        network 172.23.2.0/29
                dr 192.168.164.1
                distance 5
                router 192.168.184.1
                router 192.168.148.1


What makes me wonder is why wg0 is coming up as stubnet here,
while the MPLS links come up as network (stubnet 172.23.3.0/29 metric 
10)
and 172.23.3.0/29 (wg0 net) not being listed.

Any hints or corrections of my config to get this to work
with wireguard would be very much appreciated.