Have you used more than one roll in this camera? (just saying, it could be a problem with the film, the development, or even the ISo set wrong)
-OK, since you have more than one XA, the final answer is to compare them. Open the film back and try a couple of shots in different lighting. You should see the aperture and shutter speed change.
Compare that to one of your other cameras. My guess from the images is that you will see a noticeable difference.