well i think the consensus here is it is the substrate you are using... now dont get me wrong many of people have grown plenty of healthy plants in coco...
however there is something in ruderalis strains probably more so in the auto you have because they are extremely sensitive to pH levels and nutrients and or too little or too much at the seedling stage up until it shows its sex at or around day 20-30... then it starts to get hungry...
in order to save your plants at this point even though it is kinda late in the game to transplant even though you are probably gonna want to do it asap...
otherwise you might as well just scrub the grow so hey why not give them a chance and end up with at least some good bud at the end of all of this right???
first flush your substrate aka coco then take the plants out of their containers... then rinse off excess coco from roots then transplant gently into preferably if you have access to fox farm soil or somthing of an equivalent to light warrior or ocean forest... but do not wet the new soil as it should already be WELL moist enough right out of the bag... this will give the roots the chance to get their legs goin again and at a much faster rate so you dont lose the precious time that autos need to get the best flowering out of them...
then just simply im sure you have transplanted somethin before so you know the drill and just give them time and they should pick back up within a few days and will you have corrected the issue soon enough
good luck with the grow