Light burn or defiency

new growth is skinny with chlorosis.. too much p or k is possible. or You may have the light too close... There's not enough info. If node spacing is fine at top and no singed pistils, i'd lean toward nute-related. If you recently upped your p/k, i'd reconsider those tweaks. That's not the only possible cause .. overfeeding a slight amount may take weeks or months to show a symptom. Don't limit yourself to the most recent behaviours when trying to eliminate possibilities.