Both of my WW's were doing the same thing. The funny thing about mine is that one is in soil and the other in a hydro (drip) system. There could only be one explaination. The root systems weren't getting completely watered/O2. I had dry spots in my soil plant. Forgot to let it soak in the runoff, providing the runoff pH/ppm test OK. I used a hydrometer on the hydro plant, 3" out from the plant/ 4" down into the hydro stones. After their 15min watering it was still dry, so i upped the feed time to 30min and now all's well. There's just as much to forget as there is to learn.

Unfortunately the correction only affects new growth. In your case, the bud. The dead stuff is dead and the bad stuff won't recover. Keep your rez level a min. of 12" deep. The deeper the better, O2 diffuses better in deeper water, or get lots of air stones. I would let it do whatever it's gonna do since you're past the 1/2 way point. Hope you cut a clone.