XZ-1 Exposure Problem

I just got a XZ-1 and while in general I love the camera there is a funny issue with exposure. In automatic modes the camera tends to grossly overexpose the shots. In iAuto this happens virtually all the time, in Art Filters mode just occasional. I can get around this usually by locking exposure on a lighter area but this is a pain and takes several iterations to get it right. Any idea on what could be causing this? I have tried setting ISO to 100 or to Auto and there is no difference.

thanks,
Dave