Required Field causes Sprint value to be NULL when create an issue from Sprint

Summary:

On the Plan mode (Scrum board), under a sprint, there is a "create issue" button which will create issue to that particular sprint. The problem happens when there is a required field for issue creation. It will prompt create issue dialog box to enter the required filled, and this steps removes the value of "Sprint field" which previously has been assigned.

Steps to reproduce:

1. Go to JIRA Agile plan mode
2. Refer to the inactive sprint
3. Refer to create issue option on the bottom of that particular sprint
4. Enter the issue summary (sprint is automatically assigned to the particular sprint)
   
5. Click on "create issue" button under that particular sprint
6. It will prompt the "create issue" dialog to enter the values for required fields
7. The value of sprint becomes NULL (empty)
   
8. This causes the issue to be created in backlog
   

Expected Behavior

The value of Sprint field should not get removed when it prompts the create issue dialog box

Additional Information

• Occurs in JIRA 6.3.9 with JIRA Agile 6.6.13
• This does not occur if there is no required field (which will not prompt create issue dialog box

Workaround

The workaround would be to reenter the sprint value when the create issue dialog box is being prompted.