My opinion there is nothing to worry about. My leaves have spots and discolorations at some point in flowering all the time and yet what do you know the bud is always kick ass. '
Yes I understand, but I have plants doing it that are a month old, it's happened to at least one leaf on every strain I've grown so far, it seems to be spreading. . although it doesn't seem to slow stuff down much.
I"m certain it's not caused by a phosphorus deficiency as I'm adding a bud booster that is phosphorus, and I flushed recently. Idon't get fucked up leaves at this point in flowering ever, not 'till later on and I expect it then.
It's really hard to capture on camera.
I had it on a plant outdoors, and it grew out of it as well like someone had mentioned above, I just want to know what it is as I'm producing for a medical patient, and if it's tobacco mosiac virus I'll sterilize and start over (Not fun, but I'm also not going to provide diseased medicine.)