LDAP searches hang after returning results...

[Jeff Lebo]

OpenLDAP server setup as pass-through to AD on the backend.
When doing a traffic dump on the connection between OpenLDAP and the AD server, 
I see OpenLDAP make the search request, the AD server responds with the 
results, then it just hangs there for about 90 seconds before the OpenLDAP 
server sends an unbind request to AD.
This is causing the external application to timeout.
Any idea what is causing this?