If your in Coco, (I assume you are) you will always have a brown tint in run-off. What size pots are you running? Have you measured run off? (ppm/PH) measuring run off is important! How is your Coco built?
Autos' dont like High ppm feeds especially in Hydro, and for their size Id say 500-600ppm max. late flower. (because theyre stressed id back off to 450 ppm),
in coco/hydro you have an advantage over soil, You can do "a flush and fill" with a corrective nutrient solution. mix a 450 ppm solution (including your tap) enough for both plants. then take 3 gal of plain water pH to 5.7 pour 1.5 gal thru each pot, flushing the media, then add 1 gal of your 450 ppm nutrient mix to each pot. (do not let them sit in their run-off ever - they must be on risers - empty saucers below the riser immediately)
Raise your lights to about 3 ft set light Power @ 75%. And wait it out 3 days.
Ive run cannabis for many years, Ive seen every deficiency known, that weird pinching in the middle of the leaf I have never seen! Whenever there is weird twisting or strange leaf malformation and insects have been ruled out, I suspect root pathogens.
The clawing and the rest is an easy fix in Hydro(coco/dwc).
Flush and fill with a corrective solution - back off on light pressure. They will be stressed for a couple more days.
tip: if your running coco, build your coco to fast drain / fast dry. 55/45 #3 Perlite. Right On!