Please Help, G9 with white stains on dark pics

Hi All,

I have bought a new G9 in dealers store (un fortunatly non-cannon dealer).

While taking outdoor photos with flash I get a lot of white/transparent stains (the stains location is changed from picture to picture).

Whila taking the same photos in long exposure of the same frame, and I do not get this stains.

BTW, I can identify some stains also in outdoor - day pictures.

The dealer has sent the camers (only one month old and returned it with the claim as if there is non-issue with my camera.

Does anyone familiar with such phenomenone?

Thanks, Oren