Arduino JSON deserialization returns wrong value

Question

In my Arduino project, I have the following function:

void callback(char* topic, unsigned char* payload, unsigned int length) {
  payload[length] = '\0';
  Serial.print("Received: ");
  Serial.println(reinterpret_cast<char*>(payload));
  DynamicJsonDocument doc(1024);

  DeserializationError error = deserializeJson(doc, payload);
  if (error) {
    Serial.print("deserializeJson() failed: ");
    Serial.println(error.c_str());
  } else {
    serializeJsonPretty(doc, Serial);
    Serial.printlnln();
    int value = doc["value"];
    Serial.println(value);
  }
}

The JSON is deserialized correctly (based on the error variable and the serializeJsonPretty function), but I still get 0 for the value.

This is the function's output:

This is the output it prints:
Received: "{\"value\":1}"
"{\"value\":1}"
0

What can I do to solve this?