Micronutrient deficiency. Couldn't tell you which, because I haven't had many micro deficiencies. Without looking shit up maybe Manganese or Iron. But that just a guess.
But first I'd check pH. If the pH is off they can't get the shit they want.
You are seeing a start of potassium deficiency.
It starts at tip - it looks like nute burn. But the symptoms will move up leaf margins and tip going necrotic.
Top dress ( dry fert ) so medium can be charged and amendments to begin to breakdown for extended feeding. You can also top dress ( fresh soil / water in ) to help “ recharge “ medium.