Karbon prioritizes your Kanban board in different ways, depending on the view you're sorting by. If you're viewing work by Status, Karbon sorts the cards within a column by the Due Date (ascending). This is the same for the following views: Assignee, Client, Due Date and Related Client Group.
For the Completed Date view, columns are sorted by Completed Date, in descending order. Whereas for the Start Date view, columns are sorted by Start Date, in ascending order.
In all views, if there are Kanban cards that have the same sorting attribute (eg. the same due date), they will be displayed by the title of the work item in ascending order. If they are still matching, work items will be sorted by a unique key recorded for every Karbon work item.