your going need to flush that shit either way. if there IS anything in the soil thats causing this you will find out by flushing it and if the problem stops in a few days. if the problem continues then its something with the enviroment its in. you cant just come up to the plant and look at it and see the problem. its all just like a cross off chart. feeding it nutes wont do anything but worsen the situation, your basically playing a 50/50 game by feeding it nutes. btw cannabis plants are a weed, they could grow all on they own without any nutes. nutes only help grow faster, and stronger. doesnt mean nutes will save it. FLUSH IT AND WAIT 2 DAYS AND SEE IF THE PROBLEM STOPS, DONT BE A DUMBASS (SORRY IF IM OFFENDING YOU)
btw if you think about it, youll understand it better. your roots grow down, there could have been something in the bottom of the container and your roots just reached that something and all hell broke loss...have fun