Load cell value becomes negative when above certain force

Question

I have a 100 gram load cell with the hx711 amplifier board. I have it wired up to an arduino nano with an NRF24L01 module to send the raw value to another arduino nano. The problem is that when I aply a force to the loadcell, the value gets larger until a certain point where it becomes negative and starts to get bigger from that negative number again. So for example:

• No load : 500
• Force aplied: 1000
• More force: 1500
• More force: 2000
• More force: -2000
• More force: -1500
• More force: -1000

It is really weird. Everything worked before. I have updated the code a few times and made it simpler. I even had it set up so that the arduino only reads the value and sends it to serial monitor. That gave exactly the same behaviour. To give you a feeling for how much force is needed to reach this sort of limit. About 2 playing cards it can measure in the positive range en from 3 to 4 it becomes negative again. Then stacking to 5 or 6 it becomes positive and when 7 or 8 playing cards are on top of the loadcell the value becomes negative again.

I hope my description of the problem is sort of understandable. If more information is needed, let me know!

What could be the problem here?

EDIT: Thanks for the comments. I have found the problem: I had changed a variable in my code from long to int. That caused the problem. Here is the fixed code for anyone who is interested:

    #include "HX711.h"

    // HX711 circuit wiring
    const int LOADCELL_DOUT_PIN = 2;
    const int LOADCELL_SCK_PIN = 3;

    HX711 scale;


    #include <SPI.h>
    #include <nRF24L01.h>
    #include <RF24.h>
    RF24 radio(7, 8); // CE, CSN

    const byte address[6] = "00001";
    void setup() {
      Serial.begin(57600);
      scale.begin(LOADCELL_DOUT_PIN, LOADCELL_SCK_PIN);
      radio.begin();
      radio.openWritingPipe(address);
      radio.setPALevel(RF24_PA_MIN);
      radio.stopListening();
    }
    long reading;
    int taredone = 0;
    long tarenumber;
    void loop() {
      if (taredone == 0){
        Serial.print("15 seconds to tare");
        delay(15000);
        tarenumber = scale.read_average(20);
        Serial.print("Tarevalue: ");
        Serial.println(tarenumber);
        Serial.print("zero value: ");
        Serial.println(scale.read()-tarenumber);
        reading = 1234567890
        radio.write(&reading, sizeof(reading));
        taredone = 1;
      }
    
      if (scale.is_ready()) {
        while (true) {
          reading = scale.read_average(10)-tarenumber;
          Serial.println(reading);
          radio.write(&reading, sizeof(reading));
          delay(10);
        }
      } 
      else {
        Serial.println("HX711 not responding or no loadcell connected");
      }
    
      delay(500);

    }