lightstress, lockout, nuteburn, nute deficit, age, genetics, ...?

Hi again WeedDude! Well, she is one massive lady! It is not the fisrt time I found myself in doubt, and double check on previous week if this is really one plant. What I see is she is running out of K mate. Feeding 4 times a day (until sufficient runoff I suppose) rules out any lockout issues possible. Also, yes you are feeding at 600 ppm, but you have a lot of supplement and not enough NPK source. I don't grow with Advanced Nutrients (except for some CalMag=) so I had to check, and their feeding chart calls for 4ml a L, so giving 1,5 is really on the low side for a plant the size of yours, even for a sativa landrace. Burnt looking leaves tips and yellowing of fan leaves are the first signs of K deficiency. To fix this, up your feeding to 3ml a Litre of all 3 of your base nutrients (Grow, Micro and Bloom) as they are meant to be given at equal parts, and see if deficiency progress. Next step would be the apparition of rusty spots on leaves similar to Mag deficiency. Hope it helps!