The obvious answer is that they stopped talking about it.
My experience with GCx was that when they no longer believed something they just stopped teaching about it.
That is what I was afraid of. With this approach, they take NO responsibility for what they teach, because they are (never can be) held to account for it. A doctrine is sponsored by the National Elders, they all teach it as a group, then, when the doctrine is "out of fashion" (it is never called a false doctrine) it is simply ignored. No elder has to apologize, no National Elder is called to publicly repent. The bad doctrine simply stops getting air time.
Problem? All the old tracts, books, and audio tapes are still in circulation for anyone to get hold and read. Worse, the rank-and-file members are not clued-in that the old doctrines are biblically wrong, so they go on believing them and teaching them to their children. And none of the leadership ever has to repent in public of having taught unsound doctrine.
The "official" teaching really wasn't that "official".
This I disagree with. Anything that was taught by the National Leaders in The Cause, in book form, or sold as tracts and audio/VHS tapes by GCI is by any definition of the word, "official." If it bears the GC imprimatur on its label or cover jacket, it is official.
Official doctrine that has been found to be unsound needs to be repudiated in public, repented of (those who were subjected to the teaching need to hear an apology for being sinned against by the teachers), and the teaching must be corrected.