Issue Summary

This is reproducible on Data Center: (yes) 

In the backlog - Story View the process step filter 'doesn’t contain' brings a list of stories that contain the process step, so both 'contains' and 'doesn’t contain' filters always brings the same result

Steps to Reproduce

Prerequisites 
A Program with a PI and Sprint
A Process workflow as per the article Create Process Flow

1. After setting the process flow to the story level
2. Create a story and set a process step or mapped state
3. Go to the Backlog page and set the view to 'Story Backlog'
4. Click on 'Columns Shown' and select 'Process Step'
5. Click on 'Apply Filter'
6. Select Process Step and then select the 'doesn’t contain' option and click on 'Apply'
7. Notice that the epic that does have the process step is displayed
   
    

Expected Results

Stories that don’t contain the search content do not show in the list

Actual Results

Stories that do contain the search content show in the list

Workaround

Currently there is no known workaround for this behavior. A workaround will be added here when available