Hey guys needing help with one of two plants showing issues. It's in week 4 of flowering and seems to be flowering great but I have noticed these rust looking brown spots on the leaves. This is the only plant out of my six that is having this issue. Could this be some kind of deficiency. I'm growing in my own organic compost soil and feeding with a 3 part nutrient from blue planet. The leaves are still growing upwards toward the light and looks a healthy green except for the spots. This issue started a couple weeks ago. Haven't really noticed and bugs in room maybe one gnat the whole time, have quite a few traps set around room. Any help would be very appreciated.