Yes, it seems to be more or an issue with certain stainless vs carbon and alloy steels. It's also the nature of the attack, which cause deep penetration rather than the largely surface damage of classic rust. You can search Chloride damage in Stainless steel for plenty of detailed papers, but here's a short synopsis.

I should add, that the vast majority of stainless spokes are decently resistant to the problem. I keep two bicycles in Cozumel, MX and all 4 wheels suffered total spoke failure in 2 seasons. Since then, I've rebuilt and no issues of this kind in 6 years. Living in a harsh (salt air 99% humidity) climate, I'd much rather have SS spokes than plated, but it's important that they come from a good supplier.