Oversight, or changing conceptions?

[Galin]

I get the God metaphor, and the word "rule" is perhaps only a shorthand stand-in for something more complex here, but anyway, here's a bit of the reality for writers and storytellers.

"Last time, you said Bilbo's front door was blue, and you said Thorin had a gold tassel on his hood, but you’ve just said that Bilbo’s front door was green, and the tassel on Thorin’s hood was silver"; at which point my father muttered "Damn the boy," and then "strode across the room" to his desk to make a note."

Christopher Tolkien

Deus ex machina is another, and the eagles can be a dangerous machine, as Tolkien notes in letter 210. Of course, as the "god" of his story, Tolkien can use the eagles whenever he wants, but can he change the perception in the minds of readers that gives rise to the literary problem of God from the Machine, or the reason for Christopher Tolkien's criticism above, which can stand for more than "petty" unwanted inconsistencies.

So Christopher Tolkien, posthumously as it seems, changed Appendix F II to match Appendix F I -- for consistency I'm guessing (along with getting the "Finarfins" to match, after Finarphir in 1965). And on the other hand, some readers still wonder about the description "House of Finrod" from The Fellowship of the Ring.

I'll put it this way: I can think of an easy solution that could have avoided all this