Of course, you turned on their flowering button so now you have to wait while they switch back to the veg cycle. Next time be more patient and wait for the preflowers with your handly 10x minimum power magnifying glass to avoid that as it'll delay the overall growth plus it adds additional chance of going herm. Preflowers usually show by week 8, 10 at the latest which is about the minimum age for beginning flowering, or after alternating branching is well underway. That's always a good sign for the plant reaching maturity.