Sknowman

Looks like fade... And depending on when it started and how close to finish these are, it's a good thing(edit, because you get a better flush, the plants purging itself of excessive feed). In the last 3 weeks or so if you time your feedings right then the plant starts to cannibalize its own nutes. It starts drawing out of the large fan leaves first and you get the colour change. It's like the maple trees when their leaves go red. Since you're at week 10 I'd say you're safe... If it happens at like week 5 then you're probably dealing with lockout, and need to deal with either feeding schedule or pH