Cannot remove LDAP Directory if any LDAP group is associated with Crowd Application

If any group from the LDAP directory is associated with Crowd, removing the directory from the server or from the Crowd application results in a stack trace being displayed in the browser.

Steps to Reproduce

1. Install Crowd 2.8
2. Add an LDAP Directory
3. Go to Applications>>Crowd>>Directories and add the LDAP Directory to the Crowd application
4. Go to Applications>>Crowd>>Groups and add a group from the LDAP directory.
5. Go to Applications>>Crowd>>Directories and try to remove the LDAP Directory, a stack trace will result.
6. Go to Directories from the top menu, try removing the Directory from the Crowd instance, a stack trace will result

To workaround:
Go to Applications>>Crowd>>Groups and remove all LDAP groups before trying to disassociate the Directory or remove it from the instance.

Logs and screen shot are attached.