Pid Controller side effects

[dusty anchor]

https://youtu.be/y3K6FUgrgXw?si=RaWMUpbWTAGc38iq

Using this as source. Github of creator

https://github.com/vazgriz/PID_Controller

Then again the following fields make me seriously doubt my assumption:

public float valueLast;
    public float errorLast;
    public float integrationStored;
    public float velocity;  //only used for the info display
    public bool derivativeInitialized;