first of all,

think of this..

When bud is growing outside, it buds in late October or Sometime in November..
Go Look outside in October or November.
The leaves fall off the trees, thats what happends in fall..

When your flowering your bound to loose a bunch of leaves, thats just the way it works.

Bobby is right too, the plant is focusing way more on the buds than it is the leaves..

--I think you should be fine, just don't worry about bottom buds. I never do.

(pics?)