Well - now I am vindicated!
The collection will be called Enchanted Eve and it'll hit around October. (This information has been gleaned from Instagram and general social media, in fact personally I found it through a message on Depop)
Update: the MAC chat wherein this MAC representative confirmed it was the beloved Whisper of Gilt is actually an incompetent time waster, very annoying... It's actually called Oh, Darling and supposedly is a more yellow version. Will you still pick it up?