How long have you been flowering? It could be that the plant is finishing, the leaves die when the plant is finishing budding. read this Cannabis Nutrient And Deficiency Table - Great! about nute deficiency
I wouldnt worry too much about the yellowing, exile19 is right in saying that that often happens towards the end of flowering, the speckling on the other hand is the symptom of something else... a deficiency most likely. consult the table ^^ so you know what the issue is, not that its essential you do anything this late in flowering.