A musty odor that worsens when the AC runs can point to hidden mold in ducts or the evaporator

https://blogfreely.net/unlynnihdd/fast-ac-service-for-units-running-but-not-cooling

A musty odor that worsens when the AC runs can point to hidden mold in ducts or the evaporator. Keep the filter fresh and arrange a thorough cleaning service.