Man that is exactly my case!
Im in 5th week of flowering and my Ortega Indica has been having the exact same issue with drying out. I can not figure it out cause my other plant (master kush) is doing just good under the same conditions. I have tried to raise the humidity, but that did not help either. What goes for the leaves turning funny color, I suppose that is due to lack of light since they are shaded and located on the lower portion of the plant, that is also happening in my case.I researched this issue, but could not find any solid answers. Suggestions would really be appreciated.