HELP , dry crisping leaves ideas welcome

Completely agree with Ezzjaybruh!

This is why the ubiquitous “hit it with some cal mag” can end up compounding issues.. That said, most don’t have such a high N content

This IS a strange one to be sure... I wouldn't think it was a magnesium problem myself as that usually exhibits itself on the lower leaves first and then moves up the plant - plus, you're already giving it some calmag... I'm wondering if it could be some type of fungus... if you grasp one of those leaves, like the topmost in the first photograph - does it pull out easily? You have pretty high humidity for plants that are at this stage and so closely packed into the tent... I would examine the buds that have the dead/dying leaves for bud rot... Other than that, I have no idea - but hopefully someone else will. Meanwhile, get that humidity down into the 40s if you can... and, if possible get another fan going... good luck!

Hi there To me .. it looks like a magnesium deficiency it’s normally quite distinctive by the leaves, CalMag should sort it, Beat of luck 🌱