radvd gives 2 prefixes over same interface

[green <greenfreedom10@gmail.com>]

I am using radvd on Debian squeeze to autoconfigure clients on 2 subnets, 
2001:470:c191:1::/64 and 2001:470:c191:2::/64.  I have set up radvd.conf to use 
the first on br0 and the second on wlan1.  But when I connect with a Debian 
squeeze client over br0, the interface gets 2 global addresses, one from each 
subnet.  Any ideas what the problem is?  Thanks.

I plan to document my setup here:
http://wiki.debian.org/green/Router

### applicable portion of /etc/network/interfaces
auto br0
iface br0 inet static
  hostapd /etc/hostapd/hostapd.conf
  address 192.168.68.1
  netmask 255.255.255.0
  network 192.168.68.0
  broadcast 192.168.68.255
  bridge_ports eth1 eth2 eth3 wlan0
iface br0 inet6 static
  address 2001:470:c191:0::1
  netmask 64
iface wlan1 inet static
  address 192.168.67.1
  netmask 255.255.255.0
  network 192.168.67.0
  broadcast 192.168.67.255
iface wlan1 inet6 static
  address 2001:470:c191:1::1
  netmask 64
### end ###

### /etc/radvd.conf ###
interface br0 {
 AdvSendAdvert on;
 AdvHomeAgentFlag off;
 MinRtrAdvInterval 5;
 MaxRtrAdvInterval 15;
 prefix 2001:470:c191::/64 {
  AdvOnLink on;
  AdvAutonomous on;
  AdvRouterAddr off;
 };
};
interface wlan1 {
 AdvSendAdvert on;
 AdvHomeAgentFlag off;
 MinRtrAdvInterval 5;
 MaxRtrAdvInterval 15;
 prefix 2001:470:c191:1::/64 {
  AdvOnLink on;
  AdvAutonomous on;
  AdvRouterAddr off;
 };
};
### end ###

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