Winter squashes are high in carbohydrates. Not much less than a potato. They're pretty much always starchy. As to sweetness, they need to be fully ripe before picking.

Squashes develop starch as they mature on the vine. Perhaps with the extended season this year, the squash are just riper than usual. Personally, I like squash in that stage... but the starch will convert to sugars eventually. The slower-than-normal conversion of starch to sugars may bode well for storage life.