This is not the latest build of 9.3 but I'm guessing the problem persists.
I tried cloning a network object for another adapter on my server.
My original one was
AcmeServer1 at 192.168.2.43
Cloned it
Renamed it to AcmeServer2 and changed its IP to 192.168.1.43, I also removed the DNS stuff for this extra IP.
When trying to use AcmeServer2 for NAT rules, it does not catch the traffic, traffic is blocked and logged as a default drop. If I make a fresh Network Object that was not a clone, it was able to capture the traffic with a NAT rule.
I am not able to experiment with other instances of trying to use cloned network objects. just something to look into.