Yellowing leafs on the top

has the lamp always been that close, or did you maybe drop it closer the last week or 2 which also coincided with progression of what is seen here? If so, could be the light. otherwise, some sort of nute imbalance or buildup. The only immobile nutes (starts at top) that look like that are trace elements and those are rarely an issue. Soil should have it and if in soilless/hydro, one of the parts should contain full compliment of trace elements. This is why i mention the light first.. but if you have experience with 1' distance and no problems with that light, trust your familiarity.

Hi, I would say that it could be two problems. I mainly think that it’s nute burn. I think that the EC is to high and that the plant can’t take up water. This combined with a high vapor pressure deficit (vpd) may have stressed your plant. You have a vpd of 1.6 which is toooo high. Search up vpd calculator. Try to keep it cooler. I would also check the ppfd (light intensity) because you have 100% lights just 30cm over them. Use photone app to measure the ppfd. Hope this helps! Good luck

This is nutrient burn. Look at your leaves, they're dark green. Tips curl down and up. That's lots of nitrogen in the system. Don't add more nutes and wait for your plant to recover.