Multiple collisions not working.Plz help

Hello I am new in unity. I am experimenting collision detection using onTriggerEnter. On collision with other object(tower) direction changes and object moves. I have created one more similar object (tower) and placed both far from each other. Now for the first collision it is working fine, but at other collision it is not working, if I placed both closer to each other it works! .. I am unable to understand this phenomena, pl help Here is my code:

 void OnTriggerEnter(Collider obj) {
 
     collideCount++;
     Debug.Log(collideCount);
     
     Quaternion target = Quaternion.Euler(0, 90, 0);
     
     tf.rotation = Quaternion.Slerp(tf.rotation, target, Time.deltaTime * speed);
                   
     tf.Translate(0,6,0);
             
 }