As anyone who is familiar with the Isaac Asimov's Robots in Time series by William F. Wu is already aware, the Mojave Center Governor does not realize that sending his component parts backwards through time results in nuclear explosions and thus erasing them from history. Once the human/robot team is created to travel back in time to to retrieve the components, how does this not introduce a grandfather paradox such that the components would never have existed in that time period once they are collected?
I think SaintWacko has the answer, but this question has gone unanswered for 10 years.
The grandfather paradox is two pristine cases of event A and event not-A, where event not-A + time-travel generates event A, and event A + time-travel generates event not-A.
They inserted a second transformation into sequence such loop that did not generate state not-A, aka they removed the nuclear explosion. That stops it from being that type of loop.