I have been experiencing spikes of high latency on my WiFi (100-200ms) on my MacBook Pro M1, though I have experienced the same on my previous machine, a MacBook Pro (2020) Intel i5. I have seen a number of posts here revolving around location services and I have gone through all the troubleshooting I could find, including completely shutting off location services. As part of those troubleshooting steps, I have tried to enable WiFi logging, which unfortunately does not seem to capture anything to /var/log/wifi.log.
By complete accident, I discovered that rebooting solves the issue until I connect to my Thunderbolt 4 dock, which has a wired network connection. Upon unplugging from the dock, the latency spikes over WiFi return and will persist until I reboot. Disconnecting and reconnecting to WiFi, or disabling and re-enabling WiFi does not resolve the issue; the only thing I can find to fix it is a full reboot.
I have confirmed this also happens if I connect with a USB-C Ethernet adapter. I also believe this was happening on my previous Intel MacBook Pro, as I’d occasionally get these latency spikes, but that was before I had the dock and would only use a wired connection when transferring large files; I can’t confirm it was the same cause.
As part of my troubleshooting I’ve upgraded the wireless access point since I had plans to do that anyway, and I get the same issue.
What could cause connecting (or disconnecting) to a wired network to start interfering with my WiFi?