.empty-region-side-post.side-pre-only #region-bs-main-and-pre {
float: none;
width: auto;
}
This brought the width of the question blocks back to a normal width.
In the spirit of sharing, there is a bug with 3.2+ that thinks that there are 3 columns in our theme, and thus potentially others (as shown in the pictures). The developer of our theme took a look and was able to override this with a simple CSS line: