Yellowing and some purpling of leaves w/a month to go

Greeting fellow Farmers... I am in the final weeks of grow of 4 girls....2 bruce Banners, 1 stardawg, 1 zkittles(Auto). in the last week I have been getting/seeing a lot of yellowing of leaves and even some redding of leaves of the Zkittle and Stardawg (see pictures). The first pic is the Zkittle, the second and third pics are the bruce Banner, and the fourth is the stardawg you can see some purple on the stardawg leaves. Do you see any problems are potential problems? I think I have about a month before harvest. Could this be just a sign that they are reaching maturity? Please share your thoughts...thanks

The light colored leaves with the purple looks like P deficiency. The yellow edges on the dark plant looks like mild K deficiency.