Is this mold situation ok to ignore?
Every stick built house has mold of some type. I have worked in construction since the 70’s and well as a gopher 60’s , I currently work in a lumber mill , the boards are sprayed with a fungicide , plywood when I worked in that plant I could not believe how fast the “mushrooms” and other fungus grew on the edges of the veneer prior to being assembled. So don’t panic , proper ventilation is needed, high moisture can cause mold growth even with concrete structure. If there is real mold issues up there make sure soffit vents are clear and a ridge vent is clear I have not seen many metal vents get plugged but it can happen.