After extensive searching, I can't find any online record of the Q&A where Sanderson revealed the changed book title anywhere. While it (Skybreaker) would seem rather oddly predictive if it were completely baseless, I cannot find the source anywhere. I've found only one signing report that even mentions the idea of changing it from Stones Unhallowed (http://www.shardlabs.net/forum/topic/5853-san-francisco-wor-signing/page-3), and this was post-WoR release, after the claims that it had been changed to Skybreaker first started. Seeing how whomever changed the Goodreads article didn't bother to cite the Q&A, I'm not fully inclined to believe them. To the best of my knowlegde, the official working title is still Stones Unhallowed. Aonar Faileas (talk) 01:08, July 5, 2014 (UTC)
It is important to point out that Stones Unhallowed is now the working title likely for the fourth book in The Stormlight Archive. Brandon has already written all of Dalinar's flashback chapters for Oathbringer, now the third book in the series. Tejrinde Shahrizai (talk) 00:07, October 14, 2015 (UTC)