AccelStepper with Nema34 skips with stepper.run

Projects General Guidance
3

A, I am not allowed to

B, what does the rest have to do with this loop?

I have reduced the code to this.

/*
*/

const char compile_date[] = __DATE__;
const char compile_time[] = __TIME__;

#include <AccelStepper.h>

#define motorInterfaceType 1
#define ENABLE 7
#define DIR 6
#define PUL 8

const int SENSOR5 = 11; // digital input

int lastPosition = 0;

// Define a stepper and the pins it will use
AccelStepper stepper = AccelStepper(motorInterfaceType, PUL, DIR);
#define stepsPerRevolution 6400

void setup()
{
  Serial.begin(115200);
  while (!Serial); //Wait for the serial port to come online
  Serial.println("\n\n\n\n\n\n\n\n\n");

  Serial.print("Compiled on: ");
  Serial.print(compile_date);
  Serial.print(" at ");
  Serial.println(compile_time);


  Serial.println("Starting... ");

  // Motor controller
  pinMode(PUL, OUTPUT);    // sets the digital pin 13 as output
  pinMode(DIR, OUTPUT);    // sets the digital pin 13 as output
  pinMode(ENABLE, OUTPUT);    // sets the digital pin 13 as output
  digitalWrite(ENABLE, LOW);

  // Set the maximum speed and acceleration:
  stepper.setMaxSpeed(5000);
  stepper.setAcceleration(1000);
  stepper.setSpeed(800);

  digitalWrite(ENABLE, HIGH);

  Serial.println("End init");
}

static bool homeFound = false;

void findHome()
{
  int count = 0;
  int loops = 0;
  int value_D0 = 0;
  long currentPosition = 0;
  bool sensorFound = false;

  Serial.print("Find Home ");

  digitalWrite(ENABLE, LOW);
  stepper.setAcceleration(300);
  stepper.setSpeed(200);
  static int toMove = 6400;
  homeFound = false;

  long position = stepper.currentPosition();
  Serial.println(position);

  sensorFound =  false;
  // Wait for the motor to reach its target position

  currentPosition = stepper.currentPosition();
  Serial.print(" Forward-1: "); Serial.print(toMove);
  Serial.print(" : "); Serial.println(currentPosition);
  stepper.moveTo(toMove + currentPosition);
  while (stepper.distanceToGo() != 0) {
    value_D0 = digitalRead(SENSOR5);// reads the digital input from the sensor2
    if (value_D0 == LOW)
    {
      homeFound = true;
      break;
    }
    stepper.run();
  }
  //  delay(1000);


  if (homeFound)
    Serial.println("stop");
  else
    Serial.println("\t NO SENSOR5");
}

/****************************************************************************/

void loop()
{
  if (Serial.available())
  {
    String line = Serial.readStringUntil('\n');

    int blower = line.substring(1).toInt();
    char command = line.charAt(0);

    if (command == 'h')
    {
      Serial.println("Find Home");
      findHome();
    }
  }
}

I am not able to provide a schematic as it all goes into a pcb that is proprietary. 12v 3a power supply to TB6000.

Here is a link to a video. Notice the end. Also notice the sound. https://youtu.be/_Nu_L05lknA