Sometimes you have to set your lights to a traditional flowering schedule of 12/12 like you would if you were growing a photoperiod. It's not that rare of an occurrence actually,but after about a week or maybe 2 at most of receiving 12 hours of darkness and 12 hours of light it will trigger your auto to flower. As soon as it shows preflowers you can resume your current light schedule and it will continue flowering. Some strains just need a little push to trigger the plant to flower but whether your current light schedule is 24/0 or 20/4 or 18/6 just set your timer to 12 hours on and 12 hours off (12/12) and in a week or 2 at most you will see the pre-flowers at the node sites and can switch your timer back to it's current schedule without the plant going back into the vegetative stage. If for some reason it starts to re-veg when you resume the current light schedule then you might need to set and finish out your "autos" on a traditional 12/12 schedule, but ive never heard of that being needed , in most cases once you trigger your ladies to start flowering then you can return to your current light schedule. I hope this helps you out my fellow growmie, you can always message me if you need any more help. If I don't know the answer I can point you in the right direction of an answer. But switch those lights schedule to 12/12 immediately because keep in mind your plants are going to double or triple their current size during the flowering stretch so space might be an issue.