Entering deep sleep on an esp32 re-enables outputs

[floretan]

I have a project running on an esp32 where I only need to move a motor every few minutes, and I'm using deep sleep to reduce the power consumption. However, the motor is still powered (which probably uses more power than the esp32 itself), so I tried to call stepper.disableOutputs(), but it turns out that somehow the output pins are re-enabled when the esp32 enters deep sleep.

Here is some code to reproduce the problem:

#include <AccelStepper.h>
#define IN1 5
#define IN2 18
#define IN3 19
#define IN4 21

// Create an instance of AccelStepper
AccelStepper stepper(AccelStepper::HALF4WIRE, IN1, IN3, IN2, IN4);

void setup() {

  // Initialize the serial port
  Serial.begin(115200);

  stepper.moveTo(123);
  stepper.runToPosition();

  stepper.disableOutputs();

  sleep(3); // Wait for three seconds to have time to observe the outputs.

  // Outputs are now all low

  Serial.println("Entering deep sleep");
  esp_deep_sleep(10000000);

  // Some outputs are enabled again, reflecting the last motor position before disabling outputs.
}

I'm not sure this is relevant, but this project is using a unipolar 28BYJ-48 stepper motor.

Any idea what could be causing this issue, and how it could be possible to disable outputs while the esp is in deep sleep?