It's possible, I'll check the spokes I still have left (I hope I saved a few heads). Anyway one of the frustrations in choosing stainless steels is that those with the best chemical properties often have lousy mechanical properties, and vice versa. The 18/8 and similar alloys commonly used in quality spokes are not the most corrosion resistant (though they're not terrible), but the marine grades don't make sense for spokes.

It's possible that even quality spokes can suffer this kind of corrosion damage if submerged in a chemical soup long enough. the mechanism of corrosion resistance isn't through and through, but more of one whereby the steel forms a protective oxide skin (similar to how aluminum does it).