New xz-1 user
Almost a year ago there was an active discussion about XZ-1 smearing. This occurs when the camera is converting a raw pic to a JPG, senses noise in the pic, and is overly aggressive in eliminating the noise. The result is that the area of smearing lacks some detail and has a watercolor paint effect.
The solution is to shoot in RAW or JPG+RAW as RAW does not do any noise reduction.
I personally have taken thousands of XZ-1 pics in JPG and never seen this phenomenon. I wouldn't worry about it.