Not sure i understand you correctly.
Are you looking at outbound NAT & Inbound NAT ?
Outbound NAT:
Default all traffics passed from LAN to WAN will be NAT’d (WAN IP)
In case you don’t want the NAT you can enable “IP Forwarding”
If you found the GRE traffics is not NAT’ed, Please open a support ticket for the team to check here. This is not a expected behavior.
Inbound NAT:
Please refer to the forum thread below:
