Not an expert - just trying to think it through.
It looks like you have "boxed" a number of the spots you consider problematic, and "arrowed" the most objectionable one.
I realize your camera has a built-in self-cleaning mechanism for the sensor. It looks a lot like there may be some specks stuck to the sensor that the built-in cleaner can't get rid of. A big clue would be to note whether the spots stay in the same places for two or more different scenes. If so, I'd bet on the sensor being contaminated.
If you have access to a shop you trust, you could take it in for inspection and perhaps cleaning. I've done the cleaning myself a few times, but it is a very delicate process with the possibility of damaging the sensor. You can search WetPixel and/or the web to find out more.
If the spots move around from one scene to another, I'm stumped, unless they are somehow related to reflective surfaces having a kind of "red-eye" effect.