Isn't March typically a slow month collection wise for MAC? It seems like in the past 3 years there hasn't been a full-size collection released then. Maybe a smaller one like Dejarose and/or a collection revolving around certain products (like a lip/nail collection like Classic coordinates or the blush doubles), but not a major collection on the scale of their typical February spring collection (like Madame B or Culturebloom), early Summer collection (Sundressing, D'Bohemia, Salsabelle), etc.
MAC seems to be pretty regular in how they schedule their collections from year to year, so I'd be more surprised by a big collection (or even 3 or more smaller ones) being announced for March than there not being anything released at all.