Chosen Solution
In the middle of the S8000 lens, there is a white circular cloud the size of a dime (1 cm) that I can see in the screen and viewfinder, but only in some shots. It does show up in the finished image.
Sounds like you have condensation caught inside your lens. See if a sitting your camera on a heating pad will help speed up the evaporation. Be careful! You don’t want to cook your camera, you just want warm to the touch and don’t let it sit too long. If that fails to work its time to get your camera to a Fuji authorized service center as taking a lens apart is not easy! This is not a DIY project.