custom field updated does not reflect in the audit log

Summary

When perform modification on custom field, the changes does no reflect in the audit log.

Environment

• JIRA 6.4.12

Steps to Reproduce

1. Create a custom field of type 'Select List (single choice)' with 2 options (single word options, no strange characters)
2. Go to audit log, we can see that activity properly logged (a 'Custom field created' record has been added)
3. Now edit the configuration of the previously created custom field by adding a new option (single word option, no strange characters)

Expected Results

Go back to the audit log and there is additional log for that activity

Actual Results

Go back to the audit log and there is no additional log for that activity