Pale, light green leaves, starting from the middle to the tip. potassium?

I noticed you're VPD is off for flower...you should drop your temps to mid 70's and humidity to around 55 at least. Also I would try adding calcium to your magnesium sulfate (epsom). Sometimes providing the magnesium without the calcium can throw it out of balance and create a deficiency of one or the other(tacoing leaves). The humidity makes your leaves taco as well. I feel like once you get your VPD in line and start supplementing both calcium and magnesium she should get back on track. Hope this helps 🙏

the progression is weird.. starting from based (petiole side) and out for the paling? Do i see dots/dead spots on the one? potassium deficiency usually causes damage around tips and margins (outside perimeter of leaf. you are in a soilless medium, so calculating ppm of what you feed - individualyl and in total - would go a long way to helping deduce what is going on here. i see you recently added a product to increas P and K. if either of these are too high, they do lock out other molecules even if those other molecules are found at proper levels in the plant. if K is much higher than 200ppm, i'd supspect that is the cause, for example. a well-balanced 1.3-1.5 EC will keep 95% of plants happy. there are oddball plants out there, of course, but not nearly as common as most perceive. That's more about poorly balanced formulas. ensure pH isn't drastically different. Double check how much you are adding of each molecules... be religious with that 10% runoff waste. you have time to be a bit patient. slow moving issues = small adjustments.

looks to me like a light zn deficiency, check de ph and make sure you feed them with the right amount and frecuency.

Yea what Mrs larimar say In the second picture, see how the leaf edges are pointing upward, and the plant looks like it's praying, just like in your 8-week photo. This means it's getting a bit too much light 🍻

Hi this grow looks fantastic and the lighter leaves are lightburn, plants are to close to your light rise the light or dimm it its no calmag def. because if it were so it would be allover the leaf the yellowish parts may get bader and turn brown and wilt, if the burn was bad if its only light, they will stay like this, but the fresh grow should be without .and everyting will be fine again

Looks like cal/mag defficiency. Best to check your runoff water to see if it is a deficiency or lockout. With coco grows, cal/mag need to be added.