fragile leaves...?

so i have one flowering. looking good 2. nice buds and all that. its about 3 1/2 weeks in flowering. so im noticing that even though they look healthy, the leaves fal off very easy..i mean very easy.like i can just touch some of the larger ones and they fall right off . i assume this could be mormal as its a simulated fall season during flowering? i dunno. so i guess my question is .. is it normal to have leaves that fall off very easy during the 4th week of flowering?

no. r u talking about the newest leaves onthe bottom of the plant mostly off the secondary branching? early indication of P deficiency or Ca.

what do you mean P and Ca?
and how do i fix it?

are those the leaves in question? P=phosphorus, Ca = calcium
growing medium? nutes, water/feed sched?