Yes, it seems to be fairly consistent, and seems to match a band on my lens (see this image). I’d guess that the band is horizontal because the camera can move side to side, but not top to bottom. I don’t think that the band is an artifact of the light, nor moisture in the lens…
It would be helpful if Ricoh could confirm whether their lenses are (a) glass or plastic (b) feature a coating. While their manual says “take special care to not hit the lens”, there is no suggestion that you can’t just put down the camera.
This image of holly seems to show blurred leaves at about the same location.
