Hi @lfritz,
When the "view by type" option is chosen, the assignments would appear in whatever order the teacher has them on their assignment page. On the guide you linked, you'll see under the Assignments category that things there are not ordered by date, so this is intended functionality to give teachers more freedom to pick the order they think things should appear in (and some things may not have a date at all).
To see all dated assignments in order, students would need to use the "show by date" option and then not see the assignment category names.
I hope this explanation helps a bit.
-Chris