Trackpad moving erratically but only on left side.

Howdy! I’ve just replaced the battery and trackpad in my Early 2011 Macbook pro (the battery had swollen and warped the trackpad up partially out of the case on the keyboard side). I used iFixit parts for both. The installation went smoothly, and both parts are functioning.

But, the trackpad isn’t quite right. The left side of the trackpad responds slowly or erratically to a single finger moving the cursor. Sometimes, it is overly sensitive to tapping, meaning that it will click on things when I was just moving my finger across it. Multi touch gestures seem to work normally, even when one or more fingers are on the left side of the trackpad.

The right side of the trackpad feels and behaves exactly as the original Apple part did.

Is this likely just a defective part? I think that the trackpad is sitting properly in its spot. Clicking the trackpad feels normal on both sides. Although, facing the computer screen and looking at it from a shallow angle, the new trackpad appears to be slightly concave upward, such that there is a low spot in the middle.