Nighthawk R7000 AC1900 - latency / ping issues

Router Info:

Nighthawk R7000 AC1900

FW Version: V1.0.9.34_10.2.36

 

Symtpom Description:

All internet connections have latency go from a normal sub 30ms to > 500ms. The spike usually lasts for about 5 seconds and goes back to normal for about 30-40 seconds then back up again and so on.

 

Tests completed:

- I have attempted to monitor the latency on multiple devices, wired and wireless and they all show the same issues described above.

- I have plugged directly into my modem and the issue does not occur (very steady connection)

- I have turned all settings back to default on the router, issues persist

- After unplugging and plugging back in the issues go away for a while (up to 5 hours or so) then come back

 

Looking for advice on next steps.. thanks.