I wanted to make sure I wasn't missing something.
So,
On page 130-133 of the "manual" there is no mention of the LAN IP changing in any mode, nor what it is going to be.
And in this knowledge post https://community.cambiumnetworks.com/t5/ePMP-Configuration-Management/ePMP-Configuring-SM-units-using-the-Quick-Start-menu/m-p/96520 There is no mention of the "NEW" IP address that is assigned to the CPE once you change to NAT mode either.
While I'm sure it's buried somewhere, in some place, And because I have never used a 169.x IP in my life (mainly because I actually program radios and don't rely on back doors) I had no idea what the IP was of the radio after we "prorgrammed" it. I know this is partly my fault, and lack of knowledge of how this quick start apparently works. My simple suggestion is that you turn on DHCP server on the LAN port when selecting a mode that almost always uses DHCP server on a CLIENT radio. If I left it in bridge mode, or had it in AP mode, sure, that's not a typical setting choice. But NAT modes are typically used like that. Maybe it works properly in "router" mode, IDK. I'm looking that up now. But for me, that is counter intuitve. I don't NAT in network routers. I NAT with NAT... And when I do that on a client device, I plan to hand out an IP address to whatever is plugged in to it to NAT back to the Internet.