It sounds to me like the extractor claw is digging into the brass a little so it doesn't let go quickly enough at the proper time. Maybe some polishing of the sharp corners on that claw will resolve it?
I sent an email to Smith & Wesson Customer Service, with some pictures. I was asked to take the gun to a gunsmith for a look see and if it was determined there was an issue they would send me a mailing label to send it in. I took it back where I purchased and the owner just said it looks like the brass is hitting it on the way out, put some oil on it and clean it off. I tried and maybe got some of it off but I am still not convinced this is normal.
Not real knowledgeable about the inner working of guns so I would appreciate it if you could include a picture of the Extractor Claw you referenced.