Without looking at the assets, this is just a guess, but many assets have been turned over to the Content Repair Group to update to current standards, and I understand that these assets are somehow "hidden" so that the Content Manager will not see them as being on the DLS. I further understand that these assets are still downloadable if you ask for them explicitly, say for example as a dependency of something else. These assets might be some of them. You might be able to type the kuid directly into the Content Manager filter "by kuid" and download it from the unknown asset that I would expect to show in the window, but I won`t guarantee it.