It depends on the context and/or usage which is why the original post should really have included an complete sentence with context.Doesn't it need to be "Some sorts of X"?
That's how I see it as well. It follows the same pattern as "some type/types".It depends on the context and/or usage which is why the original post should really have included an complete sentence with context.
Some sorts of candy do not contain any fat.
This sweet thing on my plate appears to be some sort of candy.