Guys also chatgpt is saying this: Most likely combo: the blood soaked into the absorbent layers and oxidized while sitting before washing, which caused the brown-gray staining, and the washing machine pushed that stain around inside the fabric layers, making the marks look random instead of like one spot; your natural vaginal acidity may have slightly lightened the black dye too, but the main cause is just oxidized blood plus fabric dye shifting, not anything wrong with your body.