Possible nute deficiency?

I am running 2 blue dream autos under p2500 viparspectra LED. The light is 2 1/2 ft away from tallest canopy. Ph is 6.2. I have been feeding big bloom, tiger bloom Fox Farms. The medium is FFOF.

Recently I noticed some brown speckles on a few leaves. Then suddenly it has progressed. My plant is going into week 10 and the buds seem to be a bit slow to develop. Can any one help me figure what might be causing this issue?

Thank you!
Happy growing!

I think this it’s a potassium deficient, they need lots at flower stage, I think your plant has eaten up all the nutes in your fox farm, you should probably top it up it’s a supplement, I recommend giving it some cal-Mag as well, but it’s just a thought.