I returned what was a never used(it looked like it was never used) lens back to a American dealer, because it had fungus and a lot of dust. To see the dust I used a flash light. The other one went back to Japan, same story.
ALL lenses have dust.
If you had to use a flashlight to almost see any, that is normal.
Fungus is a different story and all adds seem to say fungus.
Perhaps you are seeing separation of elements etc. not fungus.