Will not focus past 12x - Vortex OPMOD Diamondback Tactical 6-24x50mm Rifle Scope, 30mm Tube, First Focal Plane (FFP)

I recently bought this scope based on the reviews and the fact that I have been very happy with all of my other vortex scopes. The scope is very clear and lets a ton of light in and finds/hold zero well. I am not sure if I have a defect but the side focus dial is very tough to turn and will not focus past about 12x power which makes the 13-24x zoom completely worthless