Very closely related: How much weight is given to authors' intentions in literary analysis?
Related (as an example of what I'm talking about): Is there any textual evidence to support that Dumbledore was gay?
Also related: Discussion in the comments on this answer.
One more example: Ray Bradbury says Fahrenheit 451 isn't about censorship. Is he right?
Certain authors, such as J. K. Rowling, are notorious for making declarations about the meaning of their text after the fact. One notable example is Rowling's claims that Dumbledore was gay. From what I've read, most people's reaction to that claim fell into one of three camps: that's great, that's terrible, and "no, she's wrong." I'm particularly interested in the "no, she's wrong" camp.
To the extent that authorial intent is relevant to meaning (and I do realize that that's a controversial point), how much weight should we give to authors' later declarations on meaning? Does there have to be some evidence that they intended that at the time that they actually wrote the book and/or some kind of indication in the text that that their claim is actually true?
To give a concrete example, does it even matter that J. K. Rowling claims that Dumbledore's gay? How much weight (if any) should we give that claim?
Another concrete example: J. K. Rowling has released additional background material (allegedly used as part of her research for the books) - e.g. character sketches, etc. Is there validity to using those for interpretation (or do we just say "no, not part of the text")?
Have there been any cases where an author's later claims about the text were clearly refuted?
Important note: I'm not asking about how authorial intent in general is related to meaning (that was already addressed in a linked post) - just how much weight later declarations that aren't clearly settled by the text should be given (like J. K. Rowling's claim).