If you have internal links in any of your “stories” , like
<a href="individual.php?pid=I12345">John Smith</a>
then you will find that the story the link is embedded in will also display on the “Stories” tab of the individual linked to.
Whilst you can certainly choose to link one story to multiple individuals, it should only happen when you choose, not when the system does it!
The fix is to replace the file kiwitrees/modules_v4/stories/module.php with the one in the attached zip folder.
You do not need to worry about this fix if you do not use the “stories” module/tab, or do not embed internal links to other individuals in your stories.