SNW S2E02 introduce a new quirk of the canon: The time “push back”, such that there will be some events (let’s just call it Canon Event) that will always come about in Prime Timeline, albeit in different actual time. Aside from the aforementioned Eugenic War, I can think of a few other so-called “inconsistency”, such as how there are already Cloaking technology for both Romulans and Klingons before Kirk’s mission, despite TOS dialogue implies that Romulan first got cloak during Kirk’s mission, and then transfer technology to Klingon. (I think the current explaination is different cloaking technology, which have various quirks.)
So here’s the question: Under what situation would you consider “Time Pushback” being an acceptable explaination for discrepancy??
A fixed point in time is literally called a ‘time crystal’ in physics.
Now that’s theory that developed after Dr Who put it out into the global conversation, much as Albucierre’s Warp theory and Star Trek. It doesn’t make it any less a completely valid science fiction explanation.
In terms of time pushing back, entropy comes into it. Pushing an essential event further down the time stream should be harder, but pushing it to an earlier date would be orders of magnitude harder. Eliminating the event altogether and forking the time steam into a new course will be much more difficult than either.
It can be argued that First Contact is classic example of time pushing back. While the Enterprise was able to ensure the first warp flight happened in the very narrow window, there were slippages in the details around the event regardless of the preservation of the date. The Prime Universe timeline was overwritten, just not as obviously as in a change of a calendar date.