So my experience with some landrace genetics from seed, growing them with no dark cycle meant that the slightest disruption caused them to start flowering. I sprayed for mites really hard one week and gave the plants 3 hours of darkness every other day to spray. I had a T5 in the corner and all the plants closest to that did not flower whereas the ones further away did. Actually I had a dozen indoor plants (from clone) that also did not flower. Speaking with the breeder of the landrace based genetics, she said that is a common trait and they most likely will not reveg, and a month later they hadn't. The ones that did not flower, I kept but have been slowly reducing the light cycle to match up with outside (june) daylight, as these are for my outdoor. I am down to 17 hours of light and have been able to keep half of my outdoor plants as the rest started flowering. My idea is that plants have a memory of sorts, and because they didn't get a dark cycle, the first time they do it triggers them to flower because to them all of a sudden the day is significantly shorter and they have never experienced that. It is a stress in other words. I'm guessing your lights went out for some reason and that is what triggered you plant and it is probably an early finisher. She might not come back around especially if you have been vegging solidly 24 hours of light. If there are any clones that haven't started flowering, you could try and give them a tiny amount of complete darkness and slowly expand on that or slowly give them darkness until you are in the complete dark, then increase the duration. I have vegged 24/7 for many years for my indoor and have never experienced this, only with the seeds, and only with these landrace based genetics.