gREEn7o0answered grow question 19 days ago It's either overwatered or under fed. Need more info.
Over fed with veg nutes would have tip burn and clawing. Looks from the pictures more like yellowing or chlorosis.
Based on the stretch/internode length its not getting too much light.
Its happening to larger and older leaves which means it's mobile.
Is the soil drying between feedings and watering, I'm guessing here but it seems like it is, I don't see the tell tale droop of overwatering, but it's hard to tell.
Overwatering can damage roots and shows up as multiple deficiencies. If you are having chlorosis and necrosis and pots aren't drying out properly you are overwatering.
Are you feeding it, if not I would start hitting with veg nutes and cal-mag.