My english leaves a lot to be desired, so please excuse any mistakes =)
I use the latest version of pfsense as the main router in the network (including ipv6), before installing mailcow ipv6 worked correctly, both with static ipv6 addresses and if ipv6 address is obtained through slaac. After installation, if I run traceroute google.com -6 from a foreign local host, the traffic will first go through the host where mailcow is running, then through the gateway of another vlan (ipv6 address of server where mailcow container 2001:470:xxxx::11, correct gateway 2001: 470:xxxx::, and the traffic goes through 2001:470:xxxx:2000:: ), I am 100% sure that the problem is because of mailcow, because if I remove the mailcow container and bridges and reboot the devices in the network, the ipv6 operation returns to normal.