Well theres a number of ideas of what it could be staring with the most probable. Yellowing browing and spotting are typical in late harvest. Your plant simply doesnt need some of its bigger fan leaves during fruiting. It also happens from foliar feeding your plants whne the lights have been on for awhile. Those could just be wet spots burnt into your plant. Also your leaves have dark green centers and fringed outer esdges which is a classic sign of over fertilizing if your not too far into bloom. The first pic actually looked pretty good