Problems with jumping after scene change

Questions & Answers
1

Hi, im creating an 2D game and everything until i created main menu. When i enter from my game scene it works good but when i enter from my main menu scene and press play it starts to jump too high… If i now go and choos game scene it does same thing but when i click my player game object in hirearchy it stops jumping high and works good… After that when i play my game scene again it works good… So in conclusion if i Use main menu scene it doesnt work, if i use game scene after pressing play at main menu scene it doesnt work. If i use ONLY game scene without previously opening main menu scene it works. Very wierd, i hope you understand :confused: In this game my player is always jumping when grounded. I dont know if you need scripts aswell so im going to put them all here.

PlayerMotor:

public float jumpPower = 10.0f;
public float speed = 2.0f;
Rigidbody2D myRigidbody;
bool isGrounded = false;

// Start is called before the first frame update
void Start()
{
    myRigidbody = transform.GetComponent<Rigidbody2D>();
}

// Update is called once per frame
void Update()
{
    if (isGrounded)
    {
        myRigidbody.AddForce(Vector3.up * (jumpPower  * myRigidbody.gravityScale * 20.0f));
    }

    if (Input.GetKey(KeyCode.LeftArrow))
    {
        myRigidbody.velocity = new Vector2(speed * -1, myRigidbody.velocity.y);
    }
    //else
    //{
    //    myRigidbody.constraints = RigidbodyConstraints2D.FreezePositionX;
   // }
    if (Input.GetKey(KeyCode.RightArrow))
    {
        myRigidbody.velocity = new Vector2(speed, myRigidbody.velocity.y);
    }
    // else
    // {
    //    myRigidbody.constraints = RigidbodyConstraints2D.FreezePositionX;
    // }
    if (!Input.GetKey(KeyCode.LeftArrow) && !Input.GetKey(KeyCode.RightArrow))
    {
        myRigidbody.constraints = RigidbodyConstraints2D.FreezePositionX;
        myRigidbody.constraints = RigidbodyConstraints2D.FreezeRotation;
    }
    else
    {
    myRigidbody.constraints = RigidbodyConstraints2D.None;
    myRigidbody.constraints = RigidbodyConstraints2D.FreezeRotation;
    }


void OnCollisionEnter2D(Collision2D other)
{
    if (other.collider.tag == "Ground")
    {
        isGrounded = true;
    }
}

void OnCollisionStay2D(Collision2D other)
{
    if (other.collider.tag == "Ground")
    {
        isGrounded = true;
    }
}

void OnCollisionExit2D(Collision2D other)
{
    if (other.collider.tag == "Ground")
    {
        isGrounded = false;
    }
}

CameraMovement:

Transform CamTransform;
public Transform Player;
public float followspeed;

{
        CamTransform = Camera.main.transform;
}

// Update is called once per frame
void Update()
{
    Vector3 targetPosition = new Vector3(Player.position.x, CamTransform.position.y, CamTransform.position.z);

    CamTransform.position = Vector3.Lerp(CamTransform.position, targetPosition, Time.deltaTime * followspeed);
}

MainMenu:

public void PlayGame()
{
    SceneManager.LoadScene(SceneManager.GetActiveScene().buildIndex + 1);
}

public void QuitGame ()
{
    Application.Quit();
}
2

At a glance, I guess that you apply the jumping force over a number of frames. You stop applying jumping force when the player collider exits the ground collider. However, it is not clear when exactly that happens. It could take multiple frames. The exact number of frames will depend on your frame rate. This depends on how you loaded the game and how much CPU power is available.
You need to check whether your character is already jumping so you do not apply the force multiple times.
Physics and game logic are hard to combine. Physics will often do unexpected things and your code will have to account for all possibilities. This will trouble you some more in the future, just so you know.