are you using distilled water for the grow? if you flushed with distilled water you should used calmag. distilled water is stripped of any calcium or anything. those leaves are signs of calcium deficency. flowering plants use calcium more in this stage also, if there is a defiency you will get leaves like yours and your buds will eventually start falling over cause calcium creates plants strength in its branches and creates a more of a hardened leaf. but fill out the troubleshooters form...