You know. I have always grown in soil/soiless. And what i have noticed is that my plants always get worse after a flush( 600ppm ). Maybe its just me. But i stop flushing. even with my synthetic runs. and i stopped having those problems. Looks like they had to much n then you probably said i should back down on the nutes a bit. When ever i use to do that, i always ran into problems. Once the plant starts flowering it says to it self "phuck the leave's its time to flower" So extra n is getting dumped in them. You need to keep looking at new growth to see if its still to much N. When u go by your leaves then flush your plants thinking that there to many nutes while not knowing your plant is hungry as shit. It is definitely a science and takes time to master.
But 5 weeks, i don't want to say just keep flushing because they might get worse. But, i am no expert. Hope everything turn out ok.