IPv6 being blocked by Default deny / state violation rule

[XerXes]

Hello everyone.

I am totally at loss. I have a dedicated server at Hetzner with Proxmox, and I have OPNSsense as my firewall, running as one of the virtual machines. Everything is working as expected and as it should, however; I have mailcow instance running in other virtual machine, IPv4 with port forwarding is working without problems, however, with IPv6 it's a different story. The configuration is static, because I couldn't get DHCPv6 to assign me one. I can ping the IP from the internet and it responds, however by doing nmap, the ports for the mailcow are showing as filtered, except for port 587. Everything else is not filtered, but I know that on the mailcow side the ports are open because if I take down the stack (it's running inside docker), the ports suddenly start showing as closed. I have added the rule to allow these ports from the WAN side to the mailcow virtual machine IPv6 address, but no change. I can see when doing the nmap scan in Live View that it's blocking these pings by Default deny / state violation rule.

Any help would be greatly appreciated. Thanks in advance.

Attached you will find the rule in question.