Light burn? Nute deficiency?

The new growth is looking a bit lemon lime green and the tips of the plants are yellowing. This can be caused by lighting being to close the the plant leaves are going through to many nutrients. Your on the high end of scale for auto feeding at 1.2EC, some of them do not like to go above 0.8-1.0 https://www.autoflower.net/forums/threads/med-man-method-feeding-chart-ppm-ec.47856/ its not a perfect reference needs adjustment if the plant needs less or more. As for the light, did the new one come with any par or lighting maps/suggestions for hang height? is this the new or old light on the diary? growdiaries.com/grow-lights/horticulture-lighting-group-hlg/260w-qb-v2-rspec Its suggested hang height via googleing is 24" but best to contact the manufacture and get the info. Good grow lights have this in the manuals. I did find this PPFD map on one web page. https://cdn.shopify.com/s/files/1/0504/4713/files/HLG_260W_PAR_grande.jpg?v=1533054531 https://www.ledgrowlightsdepot.com/products/horticulture-lighting-group-260-watt-v2-r-spec-quantum-board-diy-kit Autos can also take lower light as well. maybe try a bit higher or lowering the feed. Test one thing at a time or you wont know what one worked out for you. Given that PPFD maps readings and assuming they are true. 24" should be fine, I'm leaning toward lowering the feed a bit. Check your runoff if that's applicable and confirm PH and EC are stable, then go from there, Best of Luck!