Manual says (p. 23)
When you import a sound to a pattern, it becomes a copy of the sound on the +Drive. The
sound is not linked to the original sound stored on the +Drive. Instead, it fully becomes a part
of the pattern.
So once your Sound is loaded in the pattern, you don’t edit the original Sound, but the local sound in the pattern.
If you want to save such changes in the original Sound in the +Drive, you have to save your local sound on top of the original Sound in the +Drive
I hope my explanation is clear enough… If not, you should read the manual a bit more ^^