It's starting of my second week switching 12/12... sorry for confusion, is this not classed as second week of flower ?
As you can see, there are divergent opinions. I'm of the opinion that roughly the first two weeks after the flip is a transition period, as
@Newty said. During that time, the plants still need as much nitrogen as they do during the vegetation stage. That's because they can "stretch" as much as 2 or 3 times their height before the flip. Near the end of the stretch, they start showing pistils and growing buds, that is, they're entering the flowering stage. I was wondering why I couldn't see much stretch. (My eyesight isn't great, though.)
I don't do much defoliation, but in this case, it probably would help. It needs to be done soon, however. They don't create many new leaves or stem growth once they're in full flower. Flowering is their priority at that stage. I'd probably start by removing fan leaves growing directly from stems and see how they respond. During flowering, they'll need less nitrogen and more phosphorus and potassium.
Otherwise, they look healthy. Out of curiosity... What are the humidity and temperature? How much light are you giving them?