CIM limited to one direction

[NIhunter]

We are using 4 CIM motors for a 8 inch mecanum drive. The robot goes forward normally and can strafe in one direction flawlessly. The problem occurs while moving backwards. As 2 CIM motors do not turn the other direction. We are using Toughbox Nano gearboxes if that helps. The jaguars blink red but the wheels refuse to turn. We were demonstrating the robot when we noticed the problem. So we did not have much time to troubleshoot. I will swap the pwm's and check the voltage going to the motors shortly. I was Just wondering if anybody had a problem like this and if they found a solution.