Send it back and let them examine & repair it ...
The mainsprings had to be replaced in our KZ's after one of our folks experienced the hammer following the slide ... We were told Wilson had received a bad batch of mainsprings, with improper temper, and the sear leaf wasn't holding its adjustment.
Also, we noticed that when the pistols came back from Wilson, the trigger pulls measured 3.5 lbs, which is a bit lighter than the 4.0-4.25lbs that some folks say they prefer ... Ours are now set to hold at 4lbs, and break by 4.25lbs ... Shooting will "lighten" them a little, and our pistols all receive 1,000 break-in rounds in the hands of the folks carrying them ...
Try to avoid allowing your pistol's slide to drop on an empty chamber as a matter of common practice ... A gunsmith or armorer may do it as part of a test, but it's not something to do everytime you unload the pistol and want to close the slide without ammunition in the pistol ...