Crispy dry margins on the upper leaves. Please see detailed pics through week 5 of flowering. Pics from different days are available.

It's most likely a defeciency in phosphorus or potassium or an overdose of another nutrient causing pk to lockout, this can also be because of too low or too high ph levels or low ppm. The buds are needing higher pk levels and are taking it from the leaves instead of your soil. Try a foliar spray with molasses on the leaves and increased bloom nutes in your waterings.

Let us know if you find a solution

I really think my pH is ok. Both plants get the same water and the other plant seems to be fine. Could low PPM cause this? I have really been on the safe side with nutrients all the way up until this intended P-K boost. Problems started before that. Over-feeding was one of the options I crossed out. I forgot to mention in my question, This plant has already been getting cal-mag for two weeks.😕

Overfeed my friend tad too much you need to flush her pal :)

Feed them some calmag, When plants are in flower they consume a lot of calmag, what you are seeing is a sign that they dont have enough calmag to photosynthesize. This is what most people call light stress as well, but its really due to the plant not being able to process that much light due to a calmag deficiency. 😎