Fade or deficiency? Day 62

a fade is a sign of deficiency, but irrelevant. These don't look underfed. They look overfed. Start of margins buning, i'd guess. A bit glossy in some pictures and curling down otherwise. Photos can play tricks, so make sure these things (related to color) are accurate when looking at them with eyes... or, if/when you remove a leaf, inspect it under normal room lighting to make sure. So, i'd dial back K and N slightly and see how that goes. as best you can without impacting other components of fertilizer. if this were soilless or hydro i could give you some simple ranges to stick to for each, but this is more complicated in your setup... have to deduce what is is accurately so you can adjust the soil next time. If you are not supplementing the soil's amendments at all, it's hard to adjust anything... maybe a little extra runoff for a couple irrigations could do enough, if it's simply "in" the soil as opposed to anythign you can withold from adding that you were doing regularly before. If this is simply in the soil, you are stuck with it... as it progresses you'll better be able to diagnose... slow progression is good.. probably won't impact harvest too much. i've seen good harvests with burnt to shit canopies before (not my grows, bwahaha, but pics i see online)

Your plants do look good. But they look a bit stressed if I'm honest. I see some curling. If 3L pot of right could me root bound. Other than that, that's all I can think of why they look like that. You have good drainage on that pot right? Also let it dry out. With a pot that size root rot could me an issue maybe check. You'll knock if it's rot The roots will me yellow and smell like wet dead leafs. With what your using should me white ass. But if its 3L and an auto it's stress. Good luck

Hola !!!! Tus plantas se ven saludables. Es normal que las hojas se pongan mas claras. Lo cual la planta esta en un periodo donde consume un poco de sus reservas de nutrientes. Suerte