Green Crack Scrog

Plants took a dive bomb this whole run has been smooth and then wammo! I have delayed putting them into flower so I can fix this issue. I feel I over fed them and they are locked out or some other type of deficiencies are happening, they look over watered but are not. They look lifeless and are growing super slow and leaves are turning brown. I flushed 1 plant tonight with 15 gallons of 6.0PH water and chased it with a gallon of 6.5ph water with flower nutrients. Runoff has been perfect at 6.5 before and during nutrient issue? How strange. Flushing PH stayed consistent and dropped slowly from 6.5 6.4 6.3 and 6.2 runoff after 15 gallons ran threw her. Hopefully have good results in the morning. Will update again in the morning g if she makes a comeback