[Outdoor] Yellowing leaves during Flowering

Hey there. First time grower. Dont have any pics at the moment but will upload as soon as I can.

I currently have 16 plants outdoors:
- 3 Fat Banana
- 3 Bubblegum XL
- 3 Amnesia Haze
- 3 Lemon Shining Silver Haze
- 4 seeds I was given that I have no idea what they are (apart that they are indica and smell fruity/citrical)

All of them are yellowing in the bottom and middle, except for the 4 seeds I was given. I feed them all equal (which is a mistake I found recently, because they dont mature equally). I feed twice a week on the GH Flora Tripack and molasses on watering days. Never had any problems with over or underfeeding during veg. As soon as I increased bloom, they started yellowing. They have been yellowing since their 2nd week of flowering (they are now on the 4th, 5th and 6th). The worst of them all is the Lemon Haze, which is a full sativa that started flowering very late.

I am trying to decipher what it can be. I have increased the nitrogen, didnt solve. Started regulating the PH to 6,5 - didnt solve... Took out some of the yellow leaves, new ones come up, so the problem remains!

I have 10 of them in 25L pots (~6.6 gallons) and 6 of them in 50L fabric pots ~13 gallons). The ones on the 50L are less yellow. Some have just 1 or 2 yellow leaves. Could it be root bound preventing the plants from getting nutrients?
Really trying to solve this. I am mid flowering, plants are between 150-170cm (except the ones I topped which are about 100cm). The plants on the 25L pots are the biggest.

leaves yellow during flower because they start looking for different nutes than they do in veg its a normal thing, the plant later in flower i wouldn't even worry about (5-6 weeks) and around the 4th week the stretching subsides and the plant doesn't have much more need for much nitrogen so if you're adding a lot its essentially just becoming salt build up in the soil.
plants that have symptoms at the lower end will most likely be their mobile nutrients lack there of so its leaching the storage of the leaves and sending it to the flower.
your mobile nutrients are Nitrogen, Phosphorous, Potassium, Magnesium and Molybdenum.
chances are its either P,K or Mag.
I'd suggest seeing that they're in flower you up those 3 nutes in your next feeding.

Most nute lines reduce N as part of the flower formula.
I think that it is ok to have a gradual fade of the lower fans as flowering progresses.
If you're seeing new growth that is yellowing, I would adjust your nute mix to bump up the N.
Pics will help with a diagnosis.