hi dude.....
it is just the senescence wich is in progress on your auto
so the brown spot results from a deficiency in calcium but it is the result of senescence...as a semi mobile nutrient the plant use calcium stored in leaves to ensure best flowering as possible if the plant need this element....
for the yellowing is the same for N wich is a totally mobile nutrient...
when the plant enters in flow the plant losse 80% of their habilities to absorb N....leaves acts like a tank to help plant to find N
So if you are in a flushing process dont do anything.....and the next time use cal mag sometimes
hope this help....happy smoking
Septoria fungus ? No it’s a deficiencies combo , the plant is running out of N and Cal that is why you have pale leaves and brown spots but you are close to harvest so There is nothing to correct here