yeah 6' away from a bulb isnt going to do anything especially when they r being shaded from higher foliage. looking at the top bud there is definately a problem i think the top bud is too close to the light and is burning. The white fan leaves indicate this i belive as well as them just looking generally dry. This kind of heat can make the pistols turn red/brown too and harvest early, how long have you been flowering?
I would cut off the buds at the top of the plant that appear ready and lower the light down close but not too close to the remaining canopy and try to encouage some bud groth on the middle and bottom sections