Issue Security: Group Custom Field Value doesn't work anymore

Original Description:

After upgrading JIRA from Version 4.3.4 to JIRA 5.1.1 we have noticed, that filters don't show any issues although the affected users do have viewer rights on the project and Issue Security is set properly by a Group Custom Field Value. It worked smoothly before the upgrade and we didn't change any configuration setting afterwards.
Is an update routine working wrong or is there any bug in the filtering code?

Steps to reproduce:

1. Create a Select List Custom Field (e.g.: 'Security Select List') and add it to the default screen;
2. Add the option 'security-test' to the custom field;
3. Add a group in JIRA called 'security-test';
4. Create an user 'testuser' and add it to the 'security-test' group;
5. Create an Issue Security Scheme;
6. Add an Issue Security Level to this scheme;
7. Grant Permissions in this Security Level for the 'Reporter' and for the 'Security Select List' custom field;
8. Create an Issue and choose the 'security-test' option for the 'Security Select List' custom field;
9. Log into JIRA using the 'testuser' user;
10. Search for the issue.

Expected Behavior:

• By typing the issue key into the quick search bar, he'd be directed to the issue.
• The 'testuser' would be able to see the Issue in the Issue Navigator.

Actual Behavior:

• The 'testuser' is able to access the issue by typing the issue key into the search bar;
• But the user is not able to find the issue in the issue navigator.

Workaround:

Replace the 'Select List' custom field with a Group Picker custom field. The Group Picker Custom Field works correctly with the Security Scheme, and the issue navigator will show the issues.

Please note that using a Group Picker Field won't work if users don't have 'Browse Users' permission due to security restrictions. In that case, you can use a scripted post-function (by Script Runner Plugin) or the Copy Value from Other Field Post-Function (from JIRA Suite Utilities) to copy the selected Group from the 'Select List' to a 'Group Picker'.