Did select comics come out early?

A day or so ago I saw early reviews for some issues. I thought nothing of it because sometimes sites get to read things early. Then today I saw some despairing remarks about what's being teased at for BaRE 3 (which sadly sounds like something I called when it was announced.) Then I went to an online store which has a few series instock while others aren't. Usually they change them all from pre-order to in stock on the same day.