I'm with m.g. on this one, as usual. 1st...Using the pro soil you are using...you don't need many ferts at all! Adding Nitrogen in the 4th week of flower is crazy...I think you got some fert burn...
yellowing leaves at the end of flower is typical and shows that the plant is using all available nitrogen/nutrients inside...you want to use all nitrogen before harvest, for better tasting smoother smoke.

I recommend you leach your soil...this is done by flushing your pots with 3x's the capacity of your containers of ph'd water...i.e. If you are in 2 gallon pots, then use 6 gallons per plant...pour it through...then don't water again until almost dry. Use a fresh batch of nutes(no nitrogen) and you should be OK. flush with nothing but ph'd water last 2-3 weeks always...
Or, As m.g. said. you could've just used water the rest of the way. flush my friend...bud will taste like chitman, if you overferted... peace