2.0.9 protocol babel issue

[admin]

Hi,there!
I upgraded Bird to 2.0.9, but the Babel protocol could not find neighbors. my 
interface link is wireguard VPN. how to solve this problem?
thank you!

this is my configuration,bird 2.0.8 is work.
protocol babel {
        ipv4 {
                export where (source = RTS_DEVICE) || (source = RTS_BABEL);
        };
        ipv6 {
                export where (source = RTS_DEVICE) || (source = RTS_BABEL);
        };
        interface "gz-*";
}