Weird channel analysis results

Hey guys,

I am seeing a weird result when analyzing the 5GHz channels from a Netgear R7800 connected to another OpenWRT AP as a 5GHz client on a DFS channel.

If an AP is on a DFS channel, I understand that the hardware used for channel analysis is busy watching for a DFS conflict. But what if it's a client not an AP?

My full setup, if someone has time to duplicate:
AP: a Linksys WRT1200AC running 23.05.0 with an 802.11ac access point configured with WPA2-PSK(CCMP) on US DFS channel 52 (80MHz). I expect the model and exact channel don't matter as long as it's a DFS channel.
Client: a Netgear X4S R7800 running 23.05.0 connecting to the above AP as a client for WAN access (repeater). I configured a 2.4GHz-only 802.11n AP, and connected to that. Then under the wireless tab, I scanned the 5GHz band, selected the Linksys AP, and connected to that, checking the "Lock to BSSID" option, which created the wwan interface.

Running a channel analysis defaults to scanning the 5GHz channels. If I just let it run under this config, I get caught in a loop where my session times out, so I login again, but that restarts the scan, the session times out, and so on.

If I switch to the 2.4GHz radio immediately on entering the channel analysis page, that scan completes showing normal results. If I then switch back to the 5GHz radio, the scan does complete, but it shows all 5GHz channels other than the local interface as 20MHz channels when I know many of them are 80MHz.

I can disable the wireless config that uses the wwan interface, then run a 5GHz channel analysis, and it shows the correct widths. I'm in a moderately light RF area, as there are just over 12 channels identified in the scan, and the DFS channel is free of interference.

There are two issues here, I believe.

  1. When analyzing the 5GHz channels while connected to a 5GHz AP as a client, it causes my login session (via a 2.4GHz connection) to timeout (only when first entering the channel analysis page).
  2. When analyzing the 5GHz channels while connected to a 5GHz AP as a client, the correct channel widths are not displayed on completion of the scan.

I have repeated the scenario several times, and it happens every time, which is the best kind of bug to track down. I just don't have enough experience to know where to look.