Bubba kush

Root issues, Likely getting a bit of rot and lacking in oxygen. Control your watering habits more and I'd also say amend more perlite into the mix next time but it looks like it has a lot. It can also do this from root damage like an aggressive topdressing or pest, but I do not think this is pest related. I also do not think this is N related. Good Luck!

Poor drainage/being waterlogged/too wet all the time.

It appears like your plant is taking Nitrogen from old leaves and moving it to new growth in the plant. Nitrogen is a mobile nutrient meaning it can be taken out of old plant tissue and moved to places where the plant thinks it needs it the most to survive. They are very smart when it comes to this. Give the plant some more Nitrogen in the next few feeding but be careful not to over do it because you are in flower and the Nitrogen uptake is much lower during flower. I hope this helps.

You are likely dealing with root rot. I’ve only experienced root rot twice and both time was on house plants that came with horrible soil. The first time I took the plant out of its container and cut away and brown mushy roots. Then replanted it into new soil. This plant did great after that. Second I was lazy and used hydrogen peroxide mix at a rate of 1 part H202 / 3 part water. Drenched the soil with it. I feel like it helped but that plant never fully recovered. You could try a repot if you can with good soil and cut away the dead root. Or you could possibly try the H202 drench. Hope this helps.

Same as last time. Root issues, Likely getting a bit of rot and lacking in oxygen. Control your watering habits more and I'd also say amend more perlite into the mix next time but it looks like it has a lot. It can also do this from root damage like an aggressive topdressing, Good Luck!

I still think you are having issues with your roots. Adding more water will not fix the issue of rot and will make it worse. Try doing a hydrogen peroxide treatment on the plant ass see how it does. Take a pen and aerate your soil by shoving it all the way down in as far as you can go all over the place. This will get air to your root zone Hope this helps

A lot of your older questions where what is wrong with my plant and a lot of the responses were something along the line of waterlogged root rot. Was their any particular reason you flushed the substrate? Did you find out it was overloaded with nutrients and it needed to be done? Or how did you come to this conclusion that the flush was the reasonable thing to do. The the only reason you do this kinda of thing is if the plant is having a major issues with buildup. and I did not see that in your plants. Given that flushing uses a shit ton of water and saturates the soil it likely made the existing problem "rot root and bad watering practices" worse, now their is no nutrition in the soil for the plants as you washed it all out and added a new stresser of being overwatered. again. Soil is hard to flush as it normally holds onto much more water then soilless mixes with perlite. If the two you flushed are bottom left and top right it shows. the top left and bottom right look fine. Give them some feed after any flush and just wait. Maybe back off the light a bit to give them time to remover, can pretend its like an over cast day but keep up all the air circulation to help dry out the soils. Next water add in some beneficial microbes to help off set the root rot and add in some enzymes if you got em. The damage is done and it will not recover but you should be able to stop it from progressing. Also don't water till the plant shows signs it wants water and water as needed not on a set schedule/amount. Some of the plants likely have a better root mass / metabolism and they will be drinking more then their peers given they are not stressed out and healthier. Allowing the soil to get dry will help the roots reestablish themselves. I use a Yucca extract in my water to help it hydrate and I water in slowly as not to overload it and skip past dry spots. Good Luck!