Deficiency. Plain and simple.
Fox farm line up is meant to be used together. You don't have to use every single bottles, but the base nutrients, the Trio of Grow Big, Big Bloom, and Tiger Bloom is really meant to be in every feedings. This is like I've said, your base nutrients and all 3 complete each other to provide the complete balance for a cannabis plant.
You are NOT! overfeeding P-K!! You are feeding half a teaspoon of Big Bloom and Tiger Bloom, feeding chart calls for 3 and 2 teaspoon of each.
You do NOT! have N toxicity! you need to bring back Grow Big in your feedings.