WhAcKeD--You were what 13 hour on and 11 hours off?? Hopefully being 3 weeks into flowering they did start showing their sex long ago.
If they still aren't showing sex, I'd make sure to correct the timer. I'd imagine you should be fine and everything most likely took off like it was supposed to do. It's the 11 hours of dark that would of had to caused the plant to think it was in flowering mode now.
I've grown purposely doing it the other way with 11 hours of light and 13 hours of darkness and one time gave them 12 hours of darkness and 8 hours of lights daily to shorten up the time it took to flower. It did speed it up, but the hours were different everyday for when the lights were on, and I thought the yields were noticeable lower. I'd doubt you have any problems that it caused, but I would switch it back to 12/12 as soon as you can.
You sure it didn't just get messed up with daylight savings time last week and not the full almost 3 weeks of flowering?? That thought crossed my mind cause I had to adjust me lights to adjust for daylight savings time, so I'm still having lights on/off at the same time of the day.
Hope nothing happened to hurt anything on your grow.
Happy Growing
Alleycat