Since when is it not possible to get a hextech chest on 3v3?

Hey, can someone tell me since when its not possible to get a hextech chest on 3v3? I played a game with Elise and got a S+, but no chest (I havn't earned a chest with Elise before). This comes as a surprise to me, as I'm pretty sure that I earned hextech chests on 3v3 before?