When browsing the "newest" books view, there are books that have been in Logos for years (some of which I own) that pop up in the sort order. eg.
Jon Courson's Application Commentary: New Testament
John MacArthur Essential Bible Study Library (25 vols.) by MacArthur, John
The Preacher's Commentary
Are all among the most recently added books according to the list. Not sure why? Not a huge issue, but can be a little confusing.