Moved in my newly built Wisconsin house in the first week of November. It's a raised ranch with unfinished full walkout basement. Insulation is fiberglass batting with 4mil poly over external wood walls, and fiberglass, no poly over foundation walls. 2X6 studs.
Decided to pull fiberglass out of one stud cavity cuz poly was cut for furnace wires and wanted to see what's what. They hadn't caulked the hole in sheathing and green spots, which appear to be mold, filled the cavity. So, just on a hunch decided to pull others around basement. Stud cavities were damp, fiberglass backs damp, and sill boxes damp with either mildew or light mold in the boxes. Pretty sure the little hole isn't to blame for the others being damp, etc.
Builder says this is natural. "Had wet fall, building is wet work, etc." Said not to worry about it and just run dehumidifier for year or two straight and all will normalize. So got two going now.
Thinking of closed cell spray foam as one mitigating tool.