You are keeping your soil too wet, for too long between waterings. You really need dry cycles with Golden Pothos. It looks like you may have a case of Powdery mildew. Powdery mildew is a fungal disease. Signs of the disease first appear as small, white spots that quickly grow and merge. Entire leaves may be covered with the thin, white layer of fungus. Here's some do's and don't's.
Do Not Crowd Plants. ...
Do Not Grow Susceptible Plants in the Shade. ...
Dispose of Infected Leaves and Stems. ...
Water the Soil, Not the Plants. ...
Buy Mildew-Resistant Varieties.