Issue Summary

Using a saved filter in the Pie chart gadget results in Total Issues JQL having the phrase AND NOT "" is EMPTY appended to the end of the filter JQL, generating the error

"Error in the JQL Query: A field name cannot be empty."

Important notes: The issue is specifically relevant when using a user or group picker type fields, ie Assignee/Team, in the Statistic Type option in the Pie Chart gadget. If you use any other non-user/group picker field types, ie Labels or Status under the Statistic Type, the Total issues JQL redirect is working as expected. 

Steps to Reproduce

1. Create a saved filter 
2. Add the Pie Chart gadget to a dashboard
3. In the "Project or Saved filter" field
   • Use your saved filter
   • Under Statistic type, select Assignee or Team
4. Save the gadget
5. Click on "Total Issues: x" to see the JQL and list of issues

See screen recording for reference: piechart-jqlerror.mp4

Expected Results

The JQL shown would match that of the saved filter and return the matching issues in the project

Actual Results

The JQL will show the saved filter query, with AND NOT "" is EMPTY appended to the end (ie, project = T1 AND resolution = Unresolved AND assignee is not EMPTY AND NOT "" is EMPTY ORDER BY priority DESC, updated DESC)

Issues are not displayed at all, and give the following error:

Error in the JQL Query: A field name cannot be empty. (line 1, character 76)

Workaround

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