Outbound NAT not working with static IP address

[BillyJoePiano]

I am having difficulty getting outbound NAT working with a static IP address configuration.  It worked fine using the default automatic configurations when it had a dynamic DHCP assignment (using another router facing the public internet) but as soon as I put OPNsense as the public-facing router with a static IP assignment, the NAT stops working.

I am watching a live packet capture of the WAN/outside interface (on Wireshark, via an SSH pipe) and it seems OPNsense is trying to route the inside packets to the ISP using their internal addresses rather than NATing the source.  However, the router itself is still sending a little traffic using the correct address of the WAN/outside interface, mostly DNS and NTP.

I'm including some screenshots of the current configuration, attached.  I did try manually setting the IPv4 Upstream Gateway in the WAN Interface configuration, but this didn't have any effect.