Help with 2D physics script

public float minGroundNormalY = .65f;
public float gravityModifier = 1f;

protected bool grounded;
protected Vector2 groundNormal;
protected Vector2 targetVelocity;
protected Vector2 velocity;
protected Rigidbody2D rb2d;
protected ContactFilter2D contactFilter;
protected RaycastHit2D[] hitBuffer = new RaycastHit2D[16];
protected List<RaycastHit2D> hitBufferList = new List<RaycastHit2D> (16);

protected const float minMoveDistance = 0.001f;
protected const float shellRadius = 0.01f;

void OnEnable () {
    rb2d = GetComponent<Rigidbody2D> ();
}

void Start () {
    contactFilter.useTriggers = false;
    contactFilter.SetLayerMask (Physics2D.GetLayerCollisionMask (gameObject.layer));
    contactFilter.useLayerMask = true;
}

void Update () {
    targetVelocity = Vector2.zero;
    ComputeVelocity ();
}

protected virtual void ComputeVelocity () {

}

void FixedUpdate () {
    velocity += gravityModifier * Physics2D.gravity * Time.deltaTime;
    velocity.x = targetVelocity.x;

    grounded = false;

    Vector2 deltaPosition = velocity * Time.deltaTime;

    Vector2 moveAlongGround = new Vector2 (groundNormal.y, -groundNormal.x);

    Vector2 move = moveAlongGround * deltaPosition.x;

    Movement (move, false);

    move = Vector2.up * deltaPosition.y;

    Movement (move, true);
}

void Movement (Vector2 move, bool yMovement) {
    float distance = move.magnitude;

    if (distance > minMoveDistance) {
        int count = rb2d.Cast (move, contactFilter, hitBuffer, distance + shellRadius);
        hitBufferList.Clear ();
        for (int i = 0; i < count; i++) {
            hitBufferList.Add (hitBuffer*);*

}
for (int i = 0; i < hitBufferList.Count; i++) {
Vector2 currentNormal = hitBufferList*.normal;*
if (currentNormal.y > minGroundNormalY) {
grounded = true;
if (yMovement) {
groundNormal = currentNormal;
currentNormal.x = 0;
}
}
float projection = Vector2.Dot (velocity, currentNormal);
if (projection < 0) {
velocity = velocity - projection * currentNormal;
}
float modifiedDistance = hitBufferList*.distance - shellRadius;*
distance = modifiedDistance < distance ? modifiedDistance : distance;
}
}
rb2d.position = rb2d.position + move.normalized * distance;
}
*This is a code I made by following this tutorial series Recorded Video Session: 2D Platformer Character Controller - Unity Learn
I ran into a problem while testing with slopes: when I hit an upward slope while moving upward the player sort of glides upward without touching the slope and then continues to jump higher even though I haven’t touched the Jump twice. Also while in this ‘gliding state’ I cannot jump. A similar thing can be achieved with hitting the bottom of a downward slope while going down.
I have no idea how to tackle this problem._

EDIT: I move the player by changing the target velocity in a computeVelocity method in another script