Issue

When using the following JQL query to search for Epics for which the "Epic Name" is empty, no results are returned:

"Epic Name" is empty

Steps to replicate

1. Create a Jira Software project
2. Create an issue in the project of type Story
3. Change the issue type to Epic. Note that you will not be asked to enter an "Epic Name" even though this field is mandatory for issues of type Epic
4. Notice that the issue was moved to the Epic type, without any Epic Name set:
   
5. Open the issue search page, and use the following JQL Query:

   "Epic Name" is empty
   

Expected results

The search should returns all the Epic for which the "Epic Name" field is empty.

Actual results

The search does not return any result:

Workaround

Run the following SQL query which will search for issues of type Epic for which the Epic Name field is empty:

select concat(concat(P.pkey,'-'),I.issuenum)
from jiraissue I
join project P on P.id = I.project
where issuetype = (select id from issuetype where pname = 'Epic')
AND I.id not in (
	select issue from customfieldvalue
	where customfield = 
	(
		SELECT id from customfield
		where customfieldtypekey = 'com.pyxis.greenhopper.jira:gh-epic-label' 
	)
);