Maybe this syslog helps
Aug 15 19:42:33 oreon mpd: [pppoe] IFACE: Up event
Aug 15 19:42:42 oreon rtadvd[939]: <make_packet> link-layer address option has null length on stf0. Treat as not included.
Aug 15 19:42:42 oreon rtadvd[940]: <sock_open> IPV6_JOIN_GROUP(link) on stf0: Can't assign requested address
Aug 15 19:42:42 oreon rtadvd[940]: <sock_open> IPV6_JOIN_GROUP(link) on stf0: Can't assign requested address
Aug 15 19:42:44 oreon rtadvd[966]: <make_packet> link-layer address option has null length on stf0. Treat as not included.
Aug 15 19:42:44 oreon rtadvd[967]: <sock_open> IPV6_JOIN_GROUP(link) on stf0: Can't assign requested address
Aug 15 19:42:44 oreon rtadvd[967]: <sock_open> IPV6_JOIN_GROUP(link) on stf0: Can't assign requested address
Aug 15 19:42:47 oreon rtadvd[993]: <make_packet> link-layer address option has null length on stf0. Treat as not included.
Aug 15 19:42:47 oreon rtadvd[994]: <sock_open> IPV6_JOIN_GROUP(link) on stf0: Can't assign requested address
Aug 15 19:42:47 oreon rtadvd[994]: <sock_open> IPV6_JOIN_GROUP(link) on stf0: Can't assign requested address