It takes a lot more time for a plant to transition from veg to flower then it does flower to veg...I'm not talking about a "reveg" (that's a plant in veg, then flowering as usual, then back to veg again) I'm saying raising from germ to the 3rd/4th leaf set on a 12/12 light cycle to sex, then going in veg mode and on their natural course from there. Flowering phase of marijuana is a "light" sensitive time for the plant...outside light sources can cause issues. Neighbors motion lights, street lights, = stagnated, airy, stretchy growth...possible hermies and or reveging. In veg, unless u have a constant of 12/12 or a constant of less then 8hrs direct sun..the cycle won't be affected...