Need help brown burnt spot on leaves , mold? Or what is it?

The pictures will say it all but I am having a bunch of brown burnt spots on leaves and I'm only 3 and a half weeks into flower so I need to fix it asap! I'm not sure if its mold like leaf spot mold, my water temperature dropped down to the mid 50s for about 5 days, humidity was in the 70s for the first 3 weeks have it down to low 60s high 50s now, daytime temp is always 82 nighttime temp is 75, not sure if thats the issue, or whatever it is I'm just not sure , any help would be VERY much appreciated!!

Spray to treat any thing recently? Or a heavy feed? Thats the way my flow charts going

Sprayed plant therapy avoht a week ago but I've sprayed that stuff 10000 times before , no heavy feeding

Looks like a sulfur deficiency

Not likely mold. Your flowering looks ok. Its on older leaves not new growth? Anything else minor oddity? Leaves breaking easy? Color, luster, thickness of leaves maybe off? The picture of the leaf you are holding may show P needs in the petiole. May... it could be genetic or normal color change too. Look at roots see if healthy and white.

Phosphorus deficiency