Maybe I failed to mention that I can see 5GHz access points when I scan for them, just like your experiment shows. But it never produces any packets in the 5GHz range when you enable monitor mode - wwd_wifi_enable_monitor_mode(). So, I believe that your experiment is not reproducing the problem that I am seeing.
Also, as confirmed in other questions I have asked on this site, setting the channel before enabling monitor mode has no effect because I am told that it always monitors for packets on all channels, which I don't believe until someone shows me that they can collect a monitor mode packet that was transmitted in the 5GHz range. It would also be helpful if when a packet arrives, it said what channel the packet was received on, which it does not.