Automatic NAT - Cannot perform Dual NAT - Actually if "allow bi-directional NAT" is checked in the NAT global properties (it is set by default), two Automatic NAT rules can match the same packet and translate the source and destination IP address simultaneously. They must both be Automatic rules and only one rule can match the source, and another different rule can only match the destination. If this situation occurs you'll see a "NAT additional rule" field in your log.
Automatic NAT - Port Forwarding not Possible - Technically correct, but port forwarding operations can be performed in a mapped service such as http_mapped without using a manual NAT rule.
Manual NAT - Proxy ARP had to be manually created - By default that is correct, but see this feature you can potentially enable in R80.10 and later: sk114395: Automatic creation of Proxy ARP for Manual NAT rules on Security Gateway R80.10
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