I'm seeing the following statistics:
WI-FI STATISTICS 2.4G
Sent :    3246599   Received :    2057484
TX Packets Dropped :    123050   RX Packets Dropped :    240
        Errors :    240
WI-FI STATISTICS 5G
Sent :    39819   Received :    0
TX Packets Dropped :    0   RX Packets Dropped :    0
        Errors :    0
I've only had this router for a week. The rate of sent packets dropped seems worrying, but it's only happening on the 2.4 GHz network. I tried disabling the 2.4 GHz network and only having the 5 GHz, but then none of my wireless clients could connect, including new 802.11ac devices that I know work on the 5 GHz band.
I'm also not sure why so much more traffic seems to be going over the 2.4 GHz network. My wireless devices include a 2015 MacBook Pro, a 2011 MacBook Pro, two current-gen iPhones (6S), and an iPad 2.
The router is running the latest firmware:   DIR-862L   Hardware Version: A1     Firmware Version: 1.02   
Is this unit a dud?