Olympus HLD-6 shutter button problem

I recently received my grip from the camera's preorder promo (yes, from March) and I noticed something odd that the trigger doesn't always work and when it does it meters and re-focuses in the center of my frame before taking the shot after a short delay after a second or so delay. Other times it focuses and snaps the picture as fast as the camera body's button.

I also noticed that the issue occurred more frequently on the 20mm Pany than on the 45mm Oly.

At first I thought that it could be due to poor lighting conditions, but although the lighting conditions didn't help I couldn't replicate the issue on the camera's shutter button.

Is there a setting I'm unaware of that may be causing this issue, or do I have to return the grip to be serviced?