Don't fret, it'd because of a couple things, first you are using bloom fertilizer which has less nitrogen, also you plants are in there fall season right now, and just as you see the plants outside changing color in the fall, cannabis does this too, more or less depending on strain.It's called hardening off, the plant is getting ready for winter and draws the mobile nutrients and sugars out of the leaves.
I like growing bubblelicious, it's one of my favorite strains and about 5 weeks into flowering her fan leaves start turning yellow and she starts dropping lower ones like crazy, she'll start turning bright green except on the smaller bud leaves, and then later into six weeks on into seven she gets some red and purplish hues in the calexes and sugar leaves, the first time i grew bubblelicious it scared me, but now it's my favorite to watch mature...so colorful..
