I have a Drobo FS which works great, but I have a Temporary Items folder in each share. Does anyone know what it creating these folders?
If you are mounting the shares to a Mac, then OS-X is likely creating them. There are other OS-X hidden files and folders that could be generated when you mount the remote share. These files and folders are usually hidden from Mac users automatically by the operating system, but they may be visible to other systems and are mostly just a nuisance.
Here are a few common ones you may find depending on Apple OS version:
Usually, you can safely ignore these folders and not worry about them unless they are causing other issues or are consuming too much disk space.