SIG's design specs call for 100% reliable extraction and ejection.
They don't care if you can't find the brass, or that it has bent case mouths.
With that said, the lost brass is a problem for a reloader.
A small dent in the case mouth is not a problem for a reloader.
I don't know of much you can do about it, short of some ejector tuning by changing the angle or length of the ejector.
I don't recommend that, as replacement parts for the P6 are getting difficult to get if you screw it up, as SIG no longer offers parts support for the P225/P6 in the United States.
rc