Why the 8.3 filenames?

Why does NeroLinux rename my files to uppercase 8.3 filenames? It only happens when I import an existing disk then add files. The added files have the correct name but the old ones get renamed. Does anyone know why?

In your Preferences…section…in ISO options…

Do you have all of the boxes checked? Joliet…64 character names…
and RockRidge extentions?