Short file name (8.3) equivalents of long file names (LFN) are created dynamically. If you have an application (or user) that relies on the 8.3 equivalent, restoring or copy these files will regenerate the short file name.

There is no fix other than to adhere to a strict 8.3 naming convention if your app must reference 8.3 names and/or your user can't be educated.