Anomalies In The Shield Of Time

In an earlier post, "The Structure of a Series: Poul Anderson" (March, 2012) here, I discussed Anderson's Time Patrol series but did not mention one query. Guion's evidence of instability in history comprises a few facts like that the precise date and text of a play on its first performance do not correspond exactly to what later scholars record. Does this mean anything other than that the scholars have got it wrong?

Let us suppose that there was a timeline in which the details occurred exactly as recorded. Because of instability, there is now a second timeline in which the details are otherwise. But surely in the second timeline events after the change should be caused by the changed version of events and therefore should include a corresponding change in what the scholars record?

Unless Guion means that the instability is such that a change can occur without affecting subsequent history? The play was seen and heard to be performed with one version of the script, yet is afterwards remembered as having been performed with a different version of the script, that different version being from the Patrol's point of view the "original" version. That would indeed make it difficult for the Patrol to monitor and guard the course of events.