The spots look like Septia... a fungus from cool wet temps and high humidity. Cut them off (looks like rust drip stains.) cut em off, and stop watering w light on, and overwatering will promote ... from what I’ve read. The water drops w light act like a magnifying glass when lights are on
Do you mean Septoria? Would be highly unlikely in an indoor operaation. However if you are in an area where the fungus is prevelant on trees or plants, most likely trees, then you may have spore on your shoes or clothes. Even that is rather improbable unless you are coming in direct contact with these palnts or downwind within like thirty yards. That being said it's good standard practice to change into clean clothes when coming inside to work in your controlled environment. If you can find a cheap set of coveralls with long sleves, change into it to work in your grow space. You can also leave a small plastic tray of light hydrogen peroxide to step in to destory spores mold and bacteria on your footwear.