The purpose of using a scrog technique is to maximize yield by shaping the plant to have more photosynthesizing surface area in the optimum space under an indoor light. What I think is happening is just that: your scrogged plants are receiving more usable light which is driving photosynthesis faster and increasing nutrient and water requirements from the root system. That root system is not keeping up with the demand and you see deficiency.

You may just need to grow more rootmass for that size plant under that much light. If the roots are healthy and have space to grow it should get better over time. You can ease stress on the plant by raising the light a bit until it's ready to handle that much.If the rootballs ARE big enough for what you're trying to do - there are a million other possible reasons why they're unable to keep up.

Thanks for the great opinion. I hadn't considered it from that aspect. It would certainly explain it.
I'm always very careful about heat, PH, air exchange, and bugs.

It's not happening at all on the non scrogged plants so perhaps your right, the scrogged plants might be just creating too much plant matter without sufficent root support. I veg the plants for 2 weeks in small pots from the time they get roots, then 2 weeks in large pots until they hit the screen enough, then 1.5-2 weeks until screen is 70% full. Then i flip to 12/12.

a 4'*'4 area contains 6 plants. Do you think that this would be sufficent time for the plants to grow a rootmass? If not... how can i increase it? I always see it as a matter of time allowed in veg. The pots are 8L autopots with 1.5L/Min air per plants. 2-4ml/Rhizotonic and 2-3ml/L Terra Vega. 2ml/L vega through weeks 1-5 flowering too.

Thank you for the advice

foliar feed! that will help get your plants healthy while your waiting for root developement. Currently there is a product call sn-14 that works well. There is another product called Ocean Grown that will be out soon. It will turn your plants green almost overnight. Place yellow sticky pads around your growing media. They will help you watch out for pests like root aphids.