This is issue is related to JRA-24558 which has been fixed and closed, but seems in JIRA 4.4.5, user who have a upper-case username are not able to search for their own issues.

Steps to reproduce:

1. Configure a LDAP connector
2. Inside the LDAP directory, Create a user with username "administrator"
3. Login with username "administrator" and create a ticket A
4. Search issues reported by 'CurrentUser()', you will find ticket A
5. Inside the LDAP directory, create a username "ADMIN"
6. Login with username "ADMIN" and create a ticket B
7. Search issues reported by 'CurrentUser()', you will NOT be able to find ticket B.

Basically, when you search 'Reporter = CurrentUser()' when your username is upper-case, you will not be able to search for your own issue has been created.