I have read on the forums about other peoples bad experience with Sig regarding malfunctioning P938s, (Sigs being reluctant to make repairs, taking 3 weeks or more to return the gun) but my experience with Sig CS has been excellent so far.
I called them on Thursday, Oct 4th, they e-mailed me a return FedEx label. Shipped it out on Friday afternoon Oct 5. Sig received it Oct 8th (7th was a holiday). I received it back today, October 12th. One week turnaround including a 3 day weekend is pretty good, I think.
The gunsmiths note said "upgraded extractor".
Off today to pick up some ammo, I hope to get to the range tomorrow to test it out.