I came across this in James Valliant's book: "...in 1996, [the Blumenthals] severed all association with an organization which had invited Branden to speak."
The organization he is referring to is undoubtedly The Objectivist Center. He just doesn't refer to it by name. Nor does he give a source for his assertion. Curious.
Probably a footnote mentioning its name
Would lend it too much fame.