text: For the rebound effect to happen, Cast Through Time needs to be on the battlefield as the spell _finishes_ resolving. For example, if you cast Warp World from your hand, and as part of its resolution it puts Cast Through Time onto the battlefield, Warp World will rebound. Conversely, if Warp World shuffles your Cast Through Time into your library as part of its resolution, and doesn’t put another one onto the battlefield, it will not rebound.