To possibly understand the relationship between an event, a clip and audio files better this might be helpful:
When working in the Sample Editor you work on clips, not events. If several events point to the same clip (the one that you alter), all of the events will of course playback the altered audio.
Usually Cubase will prompt you if you want to create a new file before working on VariAudio. It might be that you have surpressed these prompts in the past.
