Getting downlinks when using SF10

Hi,
I’m new to Lora, LoraWan, and TTN. I have built and registered a single channel gateway for testing. I basically followed Andreas Spiess’s video #134 but used the newest version 5 firmware which has a CAD mode which allows receiving on all SP’s. I built a node connected to the gateway with an Arduino UNO and a Dragino LoRa shield per Spiess’s video #117. I live in Minnesota and use frequency plan us915 and the us-west handler.
When I uplink the test payload “HI” with SP7, SP8, or SP9, is see only the uplink packets in the data and traffic for the application and gateway on the TTN console. When I uplink with SP10, I get a downlink packet for every uplink packet on SF 12 BW 500 with payload size of 22 bytes and an airtime of 329.7 msec.
The code is linked with the version 1.5.0+arduino-2 LMIC library and is not requesting confirmation.
LMIC_setTxData2(1, message, sizeof(message)-1, 0);
I have two questions:

  1. Is this a problem with the Fair Access Policy which limits downlinks?
  2. If this is a problem, how do I stop the downlinks from happening? I have checked the config files and source code for the LMIC library and the available settings for the gateway and application on TTN.
    Thanks!