Recently a (at least for me) new phenomenon appeared on the web: Faked data breaches. As the announcement of a data breach typically draws a lot of attention, it is just to be expected that faked announcements will hit the web. Additionally in a lot of media like Twitter and Facebook, speed is more important than checking back, the risk of such a faked notice to spin off is fairly high and I guess that there is no way for a response process to be able to run fast enough. Additionally, even if you figure out that it is a hoax, how can you react?
An article on CSO Online might help at least to understand, whether a report is a hoax or not: How to figure out if a data breach is a hoax