Smith and Wesson has posted a safety notice on the best carbine trainer in existence. It seems 2, yes 2, carbines have been confirmed to have had their bolts machined too shallow such that the rim of a cartridge can be crushed upon the bolt closing. This could cause the weapon to fire when pressing the bolt release after a reload or for it to fire more than once during normal firing.
S&W will send you a free gauge to check yours or if you do not feel comfortable doing it you can send in your bolt to be checked by them. I ordered a gauge by telephone by calling the following number.
Have your serial number handy and read the following safety PDF. If yours was previously checked it will have a red dot on the box it came in on the end with the label. This is unlikely as the problem was discovered in Feb 2019.
The video below shows how to check it, very simple.
They advise to not use yours until you check it. Mine has experienced no issue but I am of a mind to wait for the gauge. S&W has always exhibited great, fast service in my experience so they should arrive quickly.
Get yours checked, then get back out there and continue drilling that manipulation into your lizard brain. Tick. Tock.