Bridge device on netbsd-6

I've got a fairly recent build of netbsd6 from nyftp running on an i386 server.

I had a single wm0 interface, but I added a 4 port wm interface, so wm0 became wm4. This is fine.

However, I decided to bridge all of the wm interfaces together and I'm getting strange results. Not all interfaces are forwarding.

They look like this:

$ brconfig -a
bridge0: flags=41<UP,RUNNING>
        Configuration:
                priority 32768 hellotime 2 fwddelay 15 maxage 20
                ipfilter disabled flags 0x0
        Interfaces:
                wm4 flags=7<LEARNING,DISCOVER,STP>
                        port 5 priority 128 path cost 55 forwarding
                wm3 flags=7<LEARNING,DISCOVER,STP>
                        port 4 priority 128 path cost 55 forwarding
                wm2 flags=7<LEARNING,DISCOVER,STP>
                        port 3 priority 128 path cost 55 disabled
                wm1 flags=7<LEARNING,DISCOVER,STP>
                        port 2 priority 128 path cost 55 disabled
                wm0 flags=7<LEARNING,DISCOVER,STP>
                        port 1 priority 128 path cost 55 disabled
        Address cache (max cache: 100, timeout: 1200):
                00:26:5a:f7:87:56 wm4 282 flags=0<>
                00:11:32:04:be:0b wm3 7 flags=0<>

I don't necessarily need STP. One of the disabled interfaces in this case is plugged into a regular port, it's on a NAS, but it's not working. The connection to a wifi access point is working.

If I change which interface gets the IP address (from wm4 to wm3 or wm2 for example), the behavior of the bridge can change. Ports that weren't forwarding are now forwarding for example. In one case, I got them all working by moving the IP around a few times and using /etc/rc.d/network to restart everything.

I don't know why it was working. Now it isn't anymore.

Is the bridge device known to be broken?

Andy