If it's nutrient-related, it will present as old or new growth depending on its mobility within the plant. From what I can see, it looks prominent all over. I don't see secondary symptoms ruling out a lot of nutrients.... has to be from something affecting the plant as a whole, environment, water distribution. There are lots of environmental factors that could be at play. Rr even pests, disease, etc, hopefully someone else has more experience with this. Best of luck, shame she looks healthy otherwise.