Multiple IPv6 RAs and specific routes broken?

[Stuart D Gathman <stuart gathman org>]

I have a single default router sending RAs, and another router which 
does *not* advertise a default route, but instead advertises two 
specific routes.  I'm not sure whether NM or the kernel is to blame, but 
while radvdump shows both RAs arriving, the only route installed is the 
default route.  The specific routes are ignored.

#
# radvd configuration generated by radvdump 1.8.5
# based on Router Advertisement from fe80::20c:f1ff:fecb:6de9
# received by interface em1
#

interface em1
{
    AdvSendAdvert on;
    # Note: {Min,Max}RtrAdvInterval cannot be obtained with radvdump
    AdvManagedFlag off;
    AdvOtherConfigFlag off;
    AdvReachableTime 0;
    AdvRetransTimer 0;
    AdvCurHopLimit 64;
    AdvDefaultLifetime 0;
    AdvHomeAgentFlag off;
    AdvDefaultPreference medium;
    AdvSourceLLAddress on;

    route 2001:4830:1659:8888::/64
    {
        AdvRoutePreference high;
        AdvRouteLifetime 90;
    }; # End of route definition


    route 2001:470:8:809::/64
    {
        AdvRoutePreference high;
        AdvRouteLifetime 90;
    }; # End of route definition

}; # End of interface definition
#
# radvd configuration generated by radvdump 1.8.5
# based on Router Advertisement from fe80::862b:2bff:fe5a:191f
# received by interface em1
#

interface em1
{
    AdvSendAdvert on;
    # Note: {Min,Max}RtrAdvInterval cannot be obtained with radvdump
    AdvManagedFlag on;
    AdvOtherConfigFlag on;
    AdvReachableTime 0;
    AdvRetransTimer 0;
    AdvCurHopLimit 64;
    AdvDefaultLifetime 1800;
    AdvHomeAgentFlag off;
    AdvDefaultPreference medium;
    AdvSourceLLAddress on;

    prefix 2001:470:8:488::/64
    {
        AdvValidLifetime 2592000;
        AdvPreferredLifetime 604800;
        AdvOnLink on;
        AdvAutonomous on;
        AdvRouterAddr off;
    }; # End of prefix definition

}; # End of interface definition


# ip -6 route show

2001:470:8:488::1 via 2001:470:8:488::1 dev em1  metric 0
    cache
2001:470:8:488::50 via 2001:470:8:488::50 dev em1  metric 0
    cache
2001:470:8:488::/64 dev em1  proto kernel  metric 256
2001:470:8:809::1 via fe80::862b:2bff:fe5a:191f dev em1  metric 0
    cache
2607:f8b0:4004:801::1001 via fe80::862b:2bff:fe5a:191f dev em1 metric 0
    cache
2607:f8b0:4004:801::1008 via fe80::862b:2bff:fe5a:191f dev em1 metric 0
    cache
fe80::/64 dev em1  proto kernel  metric 256
default via fe80::862b:2bff:fe5a:191f dev em1  proto static  metric 1
default via fe80::862b:2bff:fe5a:191f dev em1  proto ra  metric 1024  
expires 1794sec