Problem: Ancestor groups of a specific instance node trigger document change events just by traversing nodes via figma plugin API.
Recording:
figma-plugin-bug.mp4 - Google Drive
Bug document:
You can reproduce this by copying the entire page from the Figma document attached above and pasting it into a blank document.
The plugin used the document-change example. GitHub - figma/plugin-samples: 
Sample Figma plugins.