excuse me, it is not a claim. it is a fact.
A fact that is inherently unprovable. Thus all anyone other that you has is "the word of some guy on the internet". Thusly, you'll have to accept it when not everyone accepts your word.
the author gave it to me, as i recall the conversation the author and i were having, included this explanation: that errata was finished and submitted, and in the queue for being added to the website. another directive which came down from higher up, moved work in another direction, effectively abandoning the website as is.
Irrelevant.
the author wanted the errata to get out there, and gave me a copy as i expressed interest in it. i am doing my part by making it available to everyone.
Irrelevant
the only way this would not be considered official is if the happenstance of it not actually getting added to the site at the last minute somehow changes the fact that it was submitted, reviewed, accepted, and queued (ie: official) in the eyes of some.
NO.
The fact that is does not have the appropriate copy-write information attached to it by WotC means that it is unofficial.
The fact that it can't have that tag put on it without someone getting sued makes it unofficial.
It being official "in the eyes of some" does not make it official.
Hyperconcious being written by Bruce dos not make it official either.
The FAQ being Q&A for D&D does not make it RAW.
The writer of the Shadowcaster having his own fixes to that class, do not make them official.
This sir, is unofficial. Is it heavily supported for its unofficial status? Yes. But it is still unofficial.
Is the only reason supposedly due to the fact that WotC lost interest in doing their jobs a really sucky thing? Yes
Will I review the errata, and likely use at least some of it? Yes, but that is my choice to do so. Because this is not RAW, this is unofficial content that I choose to accept as having come from the books author.