5Ghz Wi-Fi doesn't work if DFS channel used on TP-Link Archer C6(EU) Ver3.20

Basic working configuration:
dmesg.txt
wireless.txt

Known non-DFS channels: 36, 40, 44, 48, 149, 153, 157, and 161

Steps to reproduce:

• Set Wi-Fi 5GHz channel to 52 (dfs channel)

Result:

• 5GHz Wi-Fi stops working:

  Mon Sep 12 07:54:17 2022 daemon.notice hostapd: wlan1: interface state HT_SCAN->DFS
  Mon Sep 12 07:54:17 2022 daemon.notice hostapd: wlan1: DFS-CAC-START freq=5260 chan=52 sec_chan=1, width=1, seg0=58, seg1=0, cac_time=60s
  Mon Sep 12 07:54:17 2022 daemon.err hostapd: DFS start_dfs_cac() failed, -1
  Mon Sep 12 07:54:17 2022 daemon.err hostapd: Interface initialization failed
  

• Can't use 160Mhz bandwidth, seems because it overlaps with DFS-channels

logread.txt

System

Hardware: TP-Link Archer C6(EU) Ver3.20

Start by reviewing the attached dmesg.txt, wireless.txt, and logread.txt, then inspect the mt76 driver paths involved in DFS-CAC initialization for the MT7621-based Archer C6 v3. Reproduce the failure on channel 52 and compare it with the listed non-DFS channels. Done means 5 GHz operation succeeds on DFS channels and 160 MHz configuration is no longer blocked by the DFS handling.