Agile Stories show updated by a person who is not associated with Story when Global Rank re-evaluation takes place.

1. Hop on to Servicenow instance.
2. Create a story by impersonating a user.
3. Notice few other stories not associated with this user is being updated and updated_by for other is the user in Step 2.

The issue was happening due to Data corruption. The global rank data is corrupted, current last_index for rank_configuration is not having max global rank among the existing stories.

Run below script. It will stop same issue happening for future story creation.

var gr = new GlideAggregate('rm_story');
gr.addEncodedQuery("sys_class_name=rm_story");
gr.addAggregate("MAX", "global_rank");
gr.setGroup(false);
gr.query();
if (gr.next()){
var rankGr = new GlideRecord("rank_configuration");
rankGr.addEncodedQuery("table=rm_story^column=global_rank");
rankGr.query();
if (rankGr.next()){
rankGr.setValue("last_index", gr.getAggregate("MAX", "global_rank"));
rankGr.setWorkflow(false);
rankGr.update();
}
}