When items in Resources have been arranged with the Reorder function, adding new items can scramble the custom order of items. Several instructors at Stanford have complained about this. Every time they add new items, they have to manually adjust their items back to the order they desire. Usually, the desired order is by display name, such as Lecture 1, Lecture 2, Lecture 3, etc. This has happened with files and links. Sometimes, the order will revert to an alpha-numeric order and sometimes it will reorder in a random way that seems to have no logic to it. Instructors reporting this problem say that their items get randomly reordered.
I replicated this on sakai nightly Maintenance Branch 2.4.x (we are running 2.4.x at Stanford). I added files and reordered the files according to display name to keep them in a numerical order. I then added one extra file (Lecture 12) and the files reordered in an alpha-numeric order, Lecture 10, 11,12 appear after Lecture 1, but before Lecture 2. I removed Lecture 12, manually adjusted the order to make sure Lecture 10 and 11, went after Lecture 1-5. I then added Lecture 12 and 13 at the same time. The files got reordered in a way that doesn't even follow the alpha-numeric logic.
See screen shots. First screen shot show files that have been reordered by display name. Second screen shot shows how the files are reordered after adding one new item. Third screen shot shows how the files are reordered after adding two new items at the same time.