Using BLE via NRF24L01 to communicate with Android phone

Question

I have been going through a tutorial about this, based on the example code for the "BTLE" Arduino Library.

This is my program:

#include <SPI.h>
#include <RF24.h>
#include <BTLE.h>

RF24 radio(9,10);
BTLE btle(&radio);

void setup() {
  Serial.begin(9600);
  while (!Serial) { }
  Serial.println("BTLE advertisement receiver");
  btle.begin("");
}

void loop() {
  if (btle.listen()) {
    Serial.print("Got payload: ");
    for (uint8_t i = 0; i < (btle.buffer.pl_size)-6; i++) {
      Serial.print(char(btle.buffer.payload[i]));
    }
    Serial.println("");
  }
  btle.hopChannel();
}

I saw a video of a person running this code, and then sending advertising information via the "nRF Connect" Android app. In that video (https://www.youtube.com/watch?v=DGgjdBSId4Y) they would receive output in the Serial Monitor very regularly, as I would expect. When I run my code, and start advertising, then I see the name of my phone only every other minute in the output, and between that time, there is a lot of garbage. I cannot copy the output because of too many special characters.

I would expect the string that I am advertising to show up approximately every 100ms, as that is the rate of the advertisement.

Any idea what I could be doing wrong, or how to debug this better?