That looks like inpurities in the metal as it would be highly unlikely to be that localised if caused by a corrosive substance in the wheel. The fact that it's gone clean through is also indicative of inclusions, possible copper, in the raw material of the wheel.
The green looks like an oxide of copper that should not be there.
How old are the wheels and what does the outside of the rim look like, i.e. directly above the corrosion?
You would need an expert opinion but it looks to me like a manufacturing defect therefore replacement from the dealer.