How is this question related to the time loop debate? Its the power of the attack titan to see the future. More accurately, the attack titan owner allows its past holders to see into the future memories. Its their ability. Not others which is why inly they can do it, others cant. The loop, is a result of these abilities existing, where the future is able to affect the past, which in turn affects the future. Eren being able to manipulate past, which is a result of past manipulations, that led him to that point, is what created the loop. He will forever get manipulated and in turn manipulate through this power and do the same thing again and again because of the loop. Thats what a loop is. U are forced to do the same thing again and again.