Horrible intermittent latency on the orbi router

Thank you both for your replies!

The Firmware was recently automatically updated to the latest 2.3.1.60 firmware on both Satellite and router. 

The router has been tested in both AP and Router Mode, with the same results. At this time however, the router and satellite have been placed back into router mode.

The ISP modem is not connected to this network at this time, as this is currently being used for point to point communication within the home. ( due to the issues I suddenly started having)  

The home is approximately 2700 sqft.  The Satellite had been located approximately 40 ft from the router with no issues for over 12 months.

However during troubleshooting this was tested at various lengths, measured out for consistency,

Tested using ethernet back haul directly next to each other, and at 10 ft, 20 ft 25 ft , 30 ft, and  40 ft with the same results.

Additionally tested with wireless back haul measure out in the same increments:   10 ft, 20 ft 25 ft , 30 ft, and  40 ft with the same results.

I was able to replicate the results using just the router between wired device and wireless devices.

Several Computers where used for testing. 

2 windows based machines running windows 10 both with Wireless cards and wired gigabit ethernet ports.

2 Linux Based machines with wireless and gigabit ethernet cards.

This allowed me to confirm the same latency spikes occur regardless of a mix between wired wireless windows only, Linux only, and a windows / Liinux mix.

Each test was completed on the windows machines using the cmd prompt for simple ping testing, and win mtr for dynamic trace route results. All showing latency spikes above 3000 ms.

On the linux machine, I used the natively supported MTR and ping tools within the OS to the same result in all scenarios.

I have attempted to use all optional channels available for both 2.5 and 5ghz channels, and have toggled all available settings, such as: AP/Router mode, Beam Forming, MIMI, Daisy Chain, Fast Roaming, and unchecked the 20/40 MHZ Coexistence box.

I have rebooted the router and satellite several times, I have pin hole reset for 60/90/120 seconds the router and satellite to no avail.

I have also downgraded the firmware on both the router and satellite, which prompted the auto update, and I am still experiencing latency spikes across the LAN when isolated from the carrier Modem. 

As far as the Neighboring Wifi, I have not seen any new wifi networks set up in the area, and since I am in an "established neighborhood" I am surrounded by retirees.

While the carrier modem is not in the topography at the moment, I have had the carrier Spectrum come out and replace the modem several times.

This was done in the beginning as I had initially suspected the WAN connection to be causing the latency spikes as they were originally observed while a member of the house hold was gaming.

The modems used, all of which produced the same results where: Hitron, Technicolor, Cisco, and Ubee.

I am currently using the UBEE, When initially troubleshooting the carrier modem I ensured that each device had, Wireless, firewall, and SIP ALG disabled.

All signal levels on all carrier channels in the modem are within spec:

Currently: 

Downstream SNR: 39 dB

Upstream SNR: 38 dB

Downstream Power: 0.1 dBmv  ( Dang near perfect) 

Upstream Power: 41 dBmv   ( again excellent)

No T3 or T 4 timeouts observed.

As you can see I have been working on this for a bit, and have tried to be as systematic in my testing as possible.

A shame that one of the best routers I have ever seen has suddenly stopped working after 12 months of flawless operation.

Any help would be greatly appreciated.