Not Working Setup:
Ubuntu 14.04.2
Moodle 2.9.1
PHP 5.5.9
Apache 2.4.7
MS SQL 2008
SQL_Latin1_General_CP1_CL_AS
Compat level 100
Ansi Null and Quoted identifiers enabled
freetds .91
tds version = 8.0
MS Active Directory Functional level: Windows Server 2008 R2

Working Setup:
Ubuntu 14.04.2
Moodle 2.9.1
PHP 5.5.9
Apache 2.4.7
mysql Ver 14.14
MS Active Directory Functional level: Windows Server 2008 R2

Issue: On the MSSQL setup, when a user tries to auth against LDAP the Moodle server makes only 2 connections to the AD server with the Bind user and never sends the username. On the working mySQL connection there are 2 connections with the bind user and then a 3rd attempt with the user to be logged in.