If there are two versions of the same scene in a fiction series, how do I know which is the actual version?

Let’s say there are two versions of the same scene in a fiction series. Neither version has been revealed to be false in the story, and sometimes, the only reason for the difference is that one is the original and the other is a “special edition” or “compilation” of the original. We are not even told that there has been a retcon, so the later version could just be a different interpretation by another director/compiler.

In such a case, which version is usually deemed the “official” version?

One argument for the original is that it was what the first audiences saw/read/heard and so it would be weird to suddenly change what happened.

An argument for the newer version is that it should be assumed to be a retcon even we do not know if it really is one.

examples:

Star Wars Episode 6:
(Funeral scene at the end of the movie)
In the original movie, the ghost of Darth Vader appears as he had been just moments before he died.

In a later “special edition,” the ghost of Darth Vader appears as Anakin before he ever became Darth Vader.

Gundam Z
(Ending scene)
Originally, the young protagonist becomes mentally disabled after a grueling fight with a villain.

In a later compilation version, the young protagonist is shown to be perfectly fine after the fight with the same villain.