My K9elite does the same thing...thought I put the recoil spring on backwards at first, due to warning about this I read somewhere.
I notice that when the gun is in battery and the striker is cocked, the slide can be easily nudged backwards about 2mm (guesstimate). When the gun is fired, the slide can no longer be nudged easily. Wierd.
Never noticed this on any other gun I own; Then again the Kahr is with me everyday, and like an old friend you become quite familiar with little details.