something wrong of ifconfig bridge0 addr - mac address appears on wrong interface

[ProAce]

( untrust ) --- ( em0 , bridge0 , em1 ) --- ( trust )

Sometimes , I cannot connect to trust server from untrust.
I log some information from ifconfig bridge0 addr.
It seems some thing wrong of trust server's mac appear on em0.


trust serv1's mac: 00:50:56:af:2e:43
trust serv2's mac: 00:50:56:af:75:63


STEP1: The serv2 is not shown in bridge addr. table

   tp-fw [~] -root- ifconfig bridge0 addr
   00:50:56:af:2e:43 Vlan1 em1 1200 flags=0<>
   64:9e:f3:06:52:03 Vlan1 em0 1192 flags=0<>
   70:ca:9b:e3:a5:83 Vlan1 em0 1192 flags=0<>
   70:ca:9b:e3:a5:c3 Vlan1 em0 1200 flags=0<>

STEP2: I ping the serv2's ip from untrust , and I got 100% packet loss.

STEP3: show bridge addr. table again

   tp-fw [~] -root- ifconfig bridge0 addr
   00:50:56:af:75:63 Vlan1 em0 1198 flags=0<>
   00:50:56:af:2e:43 Vlan1 em1 1200 flags=0<>
   64:9e:f3:06:52:03 Vlan1 em0 1150 flags=0<>
   70:ca:9b:e3:a5:83 Vlan1 em0 1150 flags=0<>
   70:ca:9b:e3:a5:c3 Vlan1 em0 1200 flags=0<>

OMG! It's wrong of the 00:50:56:af:75:63 is shown with em0 interface.

STEP4: I ping the serv2's ip from tp-fw , and I got icmp reply.

STEP5: show bridge addr. table again

tp-fw [~] -root- ifconfig bridge0 addr
   00:50:56:af:75:63 Vlan1 em1 1197 flags=0<>
   00:50:56:af:2e:43 Vlan1 em1 1199 flags=0<>
   64:9e:f3:06:52:03 Vlan1 em0 1170 flags=0<>
   70:ca:9b:e3:a5:83 Vlan1 em0 1170 flags=0<>
   70:ca:9b:e3:a5:c3 Vlan1 em0 1200 flags=0<>

The 00:50:56:af:75:63 is shown with em1 interface correctly.

Why does STEP2 cause the wrong bridge addr table?
How to solve it?