When I went to the shop for my Z2, a freshly opened (purple) one had several little paint chips around the phone at that line (refer to picture marked by the arrow) revealing underneath's silver color. We opened a second box, though not as severe and visible as the first one, there were also very slight paint chipping off around the same area.
Is this a common issue? does your Z2 has paint chipping off at the edge where it starts to be a mat color (refer to picture)? now i'm worried with just a few weeks use might eventually chip it off considering it can already chip off when it's brand new. Don't remember having this issue with the Z1's paint even after a half year of heavy use!