I suggest some root zone aeration. It could be a number of things (lighting distances, temps, air flow pot/plant size)but I would start there and less nutes with next feeding or two, wouldnโt hurt to add cal/mag or top dress with natural amendments. Watch your new growth, adding root zone helpers (microbes, enzymes and living bacteria) will help quickly and noticeably and cure most root lock issues. FYI adding root zone โhelpersโ will not work if you are already using a contradicting nutrient platform, it will kill off the helpers before getting a chance to get to the root. Voodoo juice plus, IMO, is a good place to start your root zone helper research. I hope this was helpful and happy growing!
EDIT: Look in to potassium uptake if your cal/mag does not help. K is still needed, in smaller amounts, while in veg.