GUI.TextField cursor not showing in some areas

i have a GUI.TextField, when i click it the cursor is not there when i type the first letter its there, when i type the second and third letter its gone, but when i type the forth its there again. what could be causing this?

 string enteredName="";
 public GUIStyle font;

 void OnGUI(){
    GUI.matrix = Matrix4x4.TRS( Vector3.zero, Quaternion.identity, new Vector3( Screen.width / 1000f, Screen.height / 800f, 1.0f ) );
     
    enteredName = GUI.TextField(new Rect(posX,posY,sizeX,sizeY), enteredName, 25,font);
 }