Clawbot motor issue

We have one clawbot motor that will close the claws easily, but it struggles to open the claw. We just switched the motor out with a new motor and have gotten the same results. Has anyone else had this occur? Any ideas as to what is happening?
I checked to make sure the screws holding the gear framework weren’t too tight, prohibiting gear movement.
Thank you.

Maybe it’s the motor controller. That happens to our tema a lot, more so than broken motors.

Its either the motor controller or the cortex port.

Are you talking about a VEX Clawbot claw, or a custom made claw?