Physics - strange jumps.

Hello, guys! Here’s the deal:
I’ve got a 3d world with a 2d character in it (don’t let the screenshots fool you, I’ve enabled 2d for better observation). There is a capsule collider on the character. Here’s the code for it’s controller:

using UnityEngine;
using System.Collections;

public class JellyNew : MonoBehaviour {
	private GameObject child;
	public float maxSpeed = 5f; //Declare maximum speed
	bool facingRight = true;
	//Getting animator component from a child object
	public GameObject childWithAnimation; //Declaring input for editor
	Animator anim;
	void Awake () {
		anim = childWithAnimation.GetComponent<Animator> ();
	//Ground Check
	bool onGround = false;
	public Transform groundCheck;
	float groundRadius = 0.2f;
	public LayerMask whatIsGround; //Declaring input for editor
	public float jumpForce = 700f; //Declare jumping force
	//bool doubleJump = false;
	// Use this for initialization
	void Start () 
		child = GameObject.Find ("SpriteRotate"); //Finding a child which should be rotated
	// Update is called once per frame
	void FixedUpdate () 
		onGround = Physics.CheckSphere(groundCheck.position, groundRadius, whatIsGround);
		anim.SetBool("Ground", onGround);

			//doubleJump = false;
		//How fast we're moving up or down
		anim.SetFloat("vSpeed", rigidbody.velocity.y);
		float move = Input.GetAxis ("Horizontal");
		anim.SetFloat ("Speed", Mathf.Abs(move)); //This is our current vertical speed
		rigidbody.velocity = new Vector2 (move * maxSpeed, rigidbody.velocity.y);
		if(move > 0 &&!facingRight)
		else if(move < 0 && facingRight)
	void Update()
		//If player on the ground and we're hitting 'Jump' button, we become no longer 'on the ground' and we're jumping
		if(onGround  && Input.GetButtonDown("Jump"))
			anim.SetBool ("Ground", false);
			rigidbody.AddForce (new Vector2(0,jumpForce));

	void Flip() //This hideous, yet effective function rotates the child object with sprite and animation
		facingRight = 	!facingRight;
		Vector3 childScale = child.transform.localScale;
		childScale.x *= -1;
		child.transform.localScale = childScale;

When I stand on a step and jump, I jump just as I intend to - not too high up. That’s the correct version. Here’s a screen of a normal jump:

THE PROBLEM: When I run towards the stairs and jump off of one step’s edge, the character jumps enormously high. You can see how high he jumps on this screen:

What’s the problem with this all?

have a global variable that sais “LevelJumpedFrom”… and check the way you send cause effect to physics, the physics jump force musnt get anything else than level jumped from, and you should use rigidbody.velocity, its a read variable, unless you are doing something very core level in your physics… use addforce etc all the jump physics options.

dont use rigidbody.velocity to change things, it’s read only

So, guys, here’s the video I’ve made. First few times I jump when the character isn’t colliding with any steps at the moment of jumping. And as you can see he jumps almost to the top of the ladder.

But then I start running and jumping at the moment when he hits ladder collider, and you can see that he jumps much higher - he flies over the ladder.