Nighthawk CAX30S LAN Configuration

I will try to address your questions in sequence.  You write, "What else is connected to the router?"  Yes, my computer also was attached at the time, but it was assigned a different IP.
 
"Why do you think it is a "static" IP address."  Because there was nothing else attached initially.  All other devices either were off-network or offline (powered off) at the time.
 
"The modem/router doesn't control those....It is down to the devices you connect to assign their own "fixed" IP addresses."  I do know the difference between statically and dynamically assigned IPs.  Actually, the devices themselves (computer, smart phone, printer, etc.) do not assign their own IPs; this is something that generally is done manually by a human.  The fact that before I configured any such IPs on any of my devices an attached wired device with IP 192.168.1.2 appeared in the list made me "suspicious."
 
"Maybe what you see is a feature of the fact that the CAX30S is a cable modem/router."  This is my suspicion, but I am not certain since previous modem-routers were not configured in this manner.  After spending an hour or so searching various posts and threads, I could not locate anything specific to my situation so I started a new topic hoping someone might have the answer.  I did check Netgear technical support but was directed to this community, which is my reason for submitting my question(s) here first.
 
"Some things need specialist knowledge."  Yes, I think I might need to speak to a Netgear technical-support specialist.  The Netgear CAX manual refers to Ethernet link aggregation as using/requiring static IPs, but link aggregation is something else.  That is not what I am addressing, and link aggregation is turned off in my settings in any event.

It also is possible that the CAX30S/CAX30 does not support static IPs—unless aggregated—because I since have configured multiple devices with static IPs  and notice that the CAX30 assigned numerous dynamic IPs to various wireless devices that are the same as the IPs that I configured statically to some of my wired devices. That is, I now have certain wired and wireless devices using the same IPs on my network, which (obviously) should not happen.

Thank you for trying. I will attempt to locate a specialist at Netgear to call. There must be a way for me to assign static IPs to certain devices and have the CAX router recognize those static IPs so that the router does not assign those same IPs to other devices and create traffic conflicts.