bird 2.17 on NetBSD and directly connected networks

I've just replaced an archlinux system running 2.14 with a NetBSD system running 2.17. Everything seems to be working fine except that every 20 seconds it complains: KRT: Error sending route XX.XX.XX.XX/XX to kernel: File exists for each directly connected network. ie it tries to write the directly connected network entries out to the kernel routing socket and gets told they already exist. Whats going wrong here? Should it have determined that they are directly connected and not try to write them out or is it expecting the write shouldn't fail or what? cheers mark