ipv6 default route loss when app started. (using bridge)

[qwec01]

HI
Recently I encoutered a problem, my trueNAS scale 23.10.1.1 has no default ipv6 route (ipv4 is normal), so it can't be accessed via ipv6, and it can't ping any IPv6 in WAN. This machine has 1 NIC (eno1), and built a bridge named br1 with eno1 as its member.
I installed a new trueNAS in the same local network with same config, no ipv6 default route problem.
Further more, when I stop my qbittorrent app (Added external Interfaces br1) and reboot, the ipv6 default route comes back, and last forever. When I start qbittorrent app, it dessappears in 5 minutes.
Here is dmesg output.

Code:

[  124.572442] usb 1-3.3: DVB: adapter 1 frontend 0 frequency 0 out of range (174000000..862000000)
[  125.307811] usb 1-3.3: DVB: adapter 1 frontend 1 frequency 0 out of range (42000000..1002000000)
[  129.283407] usb 1-3.1: DVB: adapter 0 frontend 0 frequency 0 out of range (174000000..862000000)
[  130.015644] usb 1-3.1: DVB: adapter 0 frontend 1 frequency 0 out of range (42000000..1002000000)
(Boot completes here, below is when qbittorrent starts)
[ 9944.107308] IPv6: ADDRCONF(NETDEV_CHANGE): vethbe3cf602: link becomes ready
[ 9944.107946] IPv6: ADDRCONF(NETDEV_CHANGE): eth0: link becomes ready
[ 9944.109764] kube-bridge: port 7(vethbe3cf602) entered blocking state
[ 9944.110328] kube-bridge: port 7(vethbe3cf602) entered disabled state
[ 9944.111136] device vethbe3cf602 entered promiscuous mode
[ 9944.111655] kube-bridge: port 7(vethbe3cf602) entered blocking state
[ 9944.112188] kube-bridge: port 7(vethbe3cf602) entered forwarding state
[ 9944.176000] IPv6: ADDRCONF(NETDEV_CHANGE): net1: link becomes ready
[ 9944.179420] br1: port 2(veth83acc220) entered blocking state
[ 9944.179898] br1: port 2(veth83acc220) entered disabled state
[ 9944.180492] device veth83acc220 entered promiscuous mode
[ 9944.181122] br1: port 2(veth83acc220) entered blocking state
[ 9944.181595] br1: port 2(veth83acc220) entered listening state
[ 9946.209848] br1: port 2(veth83acc220) entered learning state
[ 9948.225829] br1: port 2(veth83acc220) entered forwarding state
[ 9948.226319] br1: topology change detected, sending tcn bpdu

because I have to use ipv6 in qbittorrent, so I can't delete br1.
I don't know wether it is a bug or is my misconfigure, thanks for your help.

 

[qwec01]

Here is br1 config and app networking config