Having Issue with Player Jumping Consistently

Hey guys so im making a platform jumper. Player jumps from platform to platform, avoiding obstacles, very normal stuff. So I created my platform for the player using normal variables like "jump, jumpheight, groundcheck, groundcheckradius" and so on. Player jumps fine (he floats a little too much in the air for my liking). Picture the platform as just a normal rectangle at this point, I only want the top of the rectangle to be "solid" so i change the offset and size of the Box Collider so the player can only stand and jump at the top and will just pass through the rest of the rectangle if they dont jump high enough.

Everything is working fine so I copy and paste the platform to have something for the player to jump to. This platform also works fine. Now I copy and paste a third platform a little higher up, this one i decide to make a little smaller (on the X axis), say instead of being 5ft long like the first two, its only 3ft. The player uses it relatively well but some spots its either a delay when he jumps, or other spots I can click the jump button as much as I want and it still doesnt jump. The specs should all be the same, I literally copy and pasted it. I adjusted the offset and size of the Box Collider for the smaller platform too just to make sure it was still only covering the proper part of the platform. Any suggestions? Ill paste my code, thanks!

 public class Controls : MonoBehaviour {
     public Rigidbody2D rb;
     public float movespeed;
     public bool moveright;
     public bool moveleft;
 
     public bool jump;
     public float jumpheight;
     public Transform groundCheck;
     public float groundCheckRadius;
     public LayerMask whatIsGround;
     private bool onGround;
 
     void Start()
     {
         rb = GetComponent<Rigidbody2D>();
 
     }
 
     void Update()
     {
 
         if (Input.GetKey(KeyCode.LeftArrow))
         {
             rb.velocity = new Vector2(-movespeed, rb.velocity.y);
 
         }
         if (Input.GetKey(KeyCode.RightArrow))
         {
             rb.velocity = new Vector2(movespeed, rb.velocity.y);
 
         }
         if (moveright)
         {
             rb.velocity = new Vector2(movespeed, rb.velocity.y);
         }
         if (moveleft)
         {
             rb.velocity = new Vector2(-movespeed, rb.velocity.y);
         }
         if (Input.GetKey(KeyCode.Space)&&onGround==true)
         {
             rb.velocity = new Vector2(rb.velocity.x, jumpheight);
         }
 
         if (jump)
         {
             rb.velocity = new Vector2(rb.velocity.x, jumpheight);
             jump = false;
         }
         {
             onGround = Physics2D.OverlapCircle(groundCheck.position, groundCheckRadius, whatIsGround);
         }
     }
     void FixedUpdate()
     {
         onGround = Physics2D.OverlapCircle(groundCheck.position, groundCheckRadius, whatIsGround);
     }
 }