I've got a feminized Cannarado Twins here that's kicked out a couple of male flowers on the same node before any pistils that I can see. It's just over a week into 12/12. The two other plants I flipped at the same time as her (a 'Plug Seedbank' Spumoni, and a 'Top Shelf Elite' San Francisco Sour Dough), have both shown pistils and no male flowers. I've got four other plants in the tent a week further into flowering (3 x Cropolope from 'Cream of the Crop', and 1 x Gorilla Girl from 'Sweet seeds'), again all female with no male flowers.
Good that this thread's here. The advice on going steady with nutrients feels like good advice. Pretty sure there aren't any light leaks, because my last few grows have been totally seed free, and all other plants in the tent are straight female. They are all in pretty hot soil though, and have just had a light feed. I've had success in the past pinching the male flowers off, and the pistils have kicked in not long after. Hopefully that will happen here, because by the sounds of it the end result is of sufficient quality to warrant a seed or two in the finished buds. I'll report back when I see how they develop.