Do you know if they removed the valve covers? These engines are bad for the roller rocker failing. The bearing for the roller fails so the roller can't turn anymore causing a ticking noise and eventual cam lobe failure. Maybe that is what your ticking noise was. Cam phasers don't really make a tick, they make more of a knock plus they were updated in 2006 so your engine has the latest parts. Its possible the rocker got pushed off the valve from a seized roller and when that happens, the valve stem gets bent so it hangs open then the piston hits it. There is no warning other than the ticking noise.