My plant is doing the same thing right now and I am in flower. I think this is a way for the plant to focus on the buding flowers rather than the foliage. You got to remember that this plant lives to die. Once in the flower stage it is going to put all of its work in to the buds hoping to pro-create.
This is natural at this point. If you start losing many layers of leaves at one point then I would get worried.
Your plants look good man!