Moving a transform behaves odd

Working on a 2D game.

So I have a Unit object prefab. The unit has a child object with a GUITexture (it's health bar)

I move the health bar guitexture if the unit moves like so:

 public void LateUpdate () {
         // if(!isSelected)
         //     return;
         _lbl.SetActive(isSelected);
         _pos = Camera.main.WorldToViewportPoint(transform.position);
         
         _pos.z = 0f;
         _pos.y = _pos.y+0.05f;
         _lbl.transform.position = _pos;
     }

The _lbl is the child object that contains the health bar.

When it was just a single object in the scene this worked perfectly. But whenever I instantiate a unit on runtime the health bar moves all jittery. Even if I drag a new object in the scene and save the scene the new object has the jitter. If i close unity and restart it and start the scene the new unit's health bar moves smooth again.

Since all units need to be dynamically instantiated this is a problem.

So to summarize:

Original object works like a charm, Object (clone) has weird jitter.

Any help with this conundrum would be greatly appreciated!