Hello @cwhogan123
It can be really hard to diagnose what may be causing something like this. But, my first thought is interference. You've checked for other WiFi systems in the area, but the spectrum used for 5GHz WiFi is unlicensed and the rules allow for using it in other ways and by other devices. In particular, things like sound bars that support wireless subwoofers and/or wireless surround speakers often use a part of the 5GHz band that is also used by Google/Nest WiFi. Worse yet, while multiple WiFi systems can share spectrum "nicely" (no impact to signal quality, but they will be sharing the capacity by taking turns), the way wireless sound bars (and things like some wireless gaming headsets) transmit audio (continuous transmission) is very different from WiFi, and the result is interference.
If your primary Google/Nest WiFi unit (the one connected to your internet service via Ethernet) is near something like a sound bar, you might try moving it further away – 10 to 15 feet would be a start, but the further the better.
If you don't have a wireless sound bar or something like a wireless gaming headset transmitter nearby, then I wouldn't rule out interference, but it seems less likely. In that case, I'd probably do a factory reset of the system and use one of the secondary units as the primary when setting it up again.
