The solution would be to use an "Allow" rule for your second rule. If you are also using loopback on your port forward you will need to use a "FWD_Fast" for traffic coming from your LAN's second rule.
Basically I only have the SAT and Allow rule coming in
<IPRule Name="Incoming_ping" Action="Allow" SourceInterface="any" SourceNetwork="all-nets" DestinationInterface="wan" DestinationNetwork="InterfaceAddresses/wan_ip" Service="all_icmp" />
<IPRule Name="Groupwise_remote" Action="SAT" SourceInterface="any" SourceNetwork="all-nets" DestinationInterface="any" DestinationNetwork="InterfaceAddresses/public_mail_ip" Service="all_services" SATTranslateToIP="InterfaceAddresses/mail_server_private_ip" />
<IPRule Name="Groupwise_allow" Action="Allow" SourceInterface="any" SourceNetwork="all-nets" DestinationInterface="any" DestinationNetwork="InterfaceAddresses/public_mail_ip" Service="all_services" />
To fix the issue, from what I understand I would have to create a rule going out?