My G22 for work did the same thing to me during a qualification, the left rear frame rail broke off. The piece stayed inside the gun and it would continue to shoot, but I had to rack the slide after every shot. This pistol had about 6K through it at the time, but we all know the .40 S&W is a lot harder on the pistols than 9mm is.
I sent it in and they replaced it and a lot of the internal springs for free. It does have a new serial number now and still shoots great. The new serial number starts with the letter "G" followed by 5 numbers.
One bit of advice though, is I would take anything that is not stock off the gun before you send it off, or you probably wont get it back.
Lawdawg