Infinite runner: obstacles not initiating correctly after the second time

Developing an infinite runner where obstacles are randomly generated (kind of a Flappy bird clone) I am using prefabs and initiate method from the code. I also use a script to initiate and then destroy the obstacle when out-of-screen The problem is, after the first initiation from the code, script doesn't seem to receive the prefab as which object to initiate, but the gameobject itself. Which in term produces problems.