From S&W
Smith & Wesson has identified a condition where, if the bolt were to fail to fully close, and the trigger is pulled, an out of battery discharge may occur. An out of battery discharge could potentially rupture an unsupported case, venting gas through the magazine well and upper receiver, and possibly fracturing a portion of the receiver.
We ask that you stop using your rifle immediately until it has been inspected and repaired as necessary.
The link has full details.
https://www.smith-wesson.com/safety/...r-safety-alert