Not In Our Yet

"'...we know only that the web [of world-lines] is troubled, not where or when the source of the disturbance lies, for that source perhaps does not exist in our yet, our reality. We can only try to trace it back up the threads.'"
-Poul Anderson, The Shield Of Time (New York, 1991), p. 135.

We think of divergent, multiple or alternative timelines but another possibility might be a single discontinuous timeline. See here, specifically the third possible solution to the causality violation paradox.

In a causal sequence, event A causes B which causes C. Thus, there is a temporal sequence, ABC. However, if A is the invention of a time machine, B is the departure of a time traveler and C is the arrival of a time traveler, then the temporal order may differ, e.g., ACB. Further, if C prevents B, thus AC(B), then the observable temporal order is AC. In this case, A occurs and would have caused B which would have caused C which, however, occurs and prevents B. Indirectly, A causes C although C may appear to be uncaused. B "...does not exist in our yet, our reality." In the discontinuous timeline scenario, B does not exist in any other reality either.

However, sometimes Time Patrollers, while experiencing an event, say that that event might be prevented and this is contradictory.