You guys have any idea what this deficiency/burn c...

All of the above solutions are correct. But I will give you an idea of why you may be having some issues. I had to read through your delightfully informative notes! That helps! You’re using a 60/40 soil+compost - perlite mix. I’ve had problems with a mix like this. The reason is that coco holds onto nutrients easily, soil has an organic property, so it’s breaking down leftovers slower. Combine all that with a good aeration medium like perlite. Your PH will be imbalanced and your medium is holding onto nutrients the plant can’t use. I would advise as others have to flush. When you do your FLUSH, start with a big dose of warm water, the same volume of the pot/soil e.g. 10gal. Wait 10 mins for the water to dissolve leftover nutrients. Then with another 2x volume of pot In water flush a second time to remove dissolved nutrients. Now moving ahead the next time you water after this flush you can continue your feed of micros and bloom nutrients go easy, feed 1/2 strength. You will have enough mobile nutrients to get you to the end. In my estimation you have 6 weeks left 4 weeks of bud growth and a 2 weeks flush. Good luck✌️🏻