Signal Problem; game controller with Teensy3.2 and Tekscan Flexiforce Sensor

Hello everybody,
i have a very strange problem with the signal of a Tekscan Flexiforce Sensor to be used in a hardware game controller (pedals).

This is my sketch:

//-------------------------------------------------------------------------------------

// Flexiforce SimCylinder Sketch
// 3x Flexiforce A301/201 Brake 1, Brake 2, Clutch
// 

//-------------------------------------------------------------------------------------

#include <ResponsiveAnalogRead.h> // https://github.com/dxinteractive/ResponsiveAnalogRead

//Pedalachsen
const int FSR_PIN1 = 20; // Flexiforce1 Bremse vorn; Pin connected to FSR/resistor divider
const int FSR_PIN2 = 21; // Flexiforce2 Bremse hinten; Pin connected to FSR/resistor divider
const int FSR_PIN3 = 22; // Flexiforce3 Kupplung; Pin connected to FSR/resistor divider
const int FLEX_PIN = 23; // Flexsensor Gas; Pin connected to voltage divider output

ResponsiveAnalogRead analog(FLEX_PIN, true);

void setup() {

  ResponsiveAnalogRead analog(FLEX_PIN, true);

  //Setup Flexiforce + Flex-Sensor
  pinMode(FSR_PIN1, INPUT); //Flexiforce1 Bremse vorn
  pinMode(FSR_PIN2, INPUT); //Flexiforce2 Bremse hinten
  pinMode(FSR_PIN3, INPUT); //Flexiforce3 Kupplung
  pinMode(FLEX_PIN, INPUT); //Flexsensor Gas

  //deactivate Joystick Hat
  Joystick.hat(-1);
  Joystick.Y(-1);

}

void loop(void) {

   
  analog.update();

  Joystick.sliderLeft(analogRead(FSR_PIN1)); // Bremskreislauf vorne
  Joystick.sliderRight(analogRead(FSR_PIN2)); // Bremskreislauf hinten oder Handbremse
  //Joystick.Y(analogRead(FSR_PIN3)); // Kupplung
  

  if (analog.hasChanged()) {
    // Input 3 axis: read analog inputs from potentiometer and set Z-position (Gas)
    Joystick.Zrotate(analogRead(FLEX_PIN)); // Achse Gas pin 23 an teensy
  }
  //delay(50);
}

The teensy is recognized as a game controller in windows, all defined axis are recognized and working.

But i have a strange problem with the signals of the Felxiforce Sensors (FSR_PIN1 and FSR
_PIN2)

Hookup is made like this as shown in a hookup guide:

https://cdn.sparkfun.com/assets/lear...ample_bb_2.png

I used the 3.3V Pin. 5V pin shows same behaviour.
One GND used for the Sensors, the other one used for the potentimoeter.

The mechanical integration looks like in this sketch:

In the Arduino Plotter the output looks like this:

When i apply pressure on the sensors the signal jumps up at a certain point and continues to raise, same behaviour when i release pressure.
The problem is not hardware or temperature related. When i change the resistor, therefore can measure higher or lower pressures, i have the signal jump at approx. the same values.
So i therefore suppose that the sensors are fine.

In my oppinion there has to be a problem in the electrical hookup or the program or whatever.

I´m really stuck here and would need some help or thoughts!?

Thanks in advance!

Cheers Dan