Country DE breaks wlan // Xiaomi Redmi Router AC2100


in the moment, I switch the wlan country to DE, I loose the connection to my Wlan (Router is client, 5GHz, WPA3 and WPA2) can someone confirm it or help? It runs with wlan country 00.

I have running too, a Xiaomi Mi Router 4A (100M Edition) in the same network (wlan country DE, 5GHz, WPA3) with no problems.
Accesspoint is an FritzBox 7590.

Both using OpenWrt 21.02.1 r16325-88151b8303 / LuCI openwrt-21.02 branch git-21.295.67054-13df80d.

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