bird 2.0.3 does not install multipath route in kernel

[Kenth Eriksson]

We have some multi-path routes that fails to get pushed into the
kernel. We are running bird 2.0.3 and kernel 4.14.92+. 


bird> show route 
...
Table master4:

10.210.138.3/32      unicast [ospf1 13:24:23.022] E1 (145/1020)
[10.210.138.3]
        via 10.210.138.2 on p1-1-1-1-2 weight 1
        via 10.210.138.2 on p1-1-5-1-6 weight 1
...
bird>

The bird log has the following warning messages (unclear if it is
related):

2019-02-28 13:30:38.343 <WARN> Netlink: Invalid argument

What is the expected behaviour for bird here? Install both routes or
just one of them?

Thanks,
Kenth