I do not have a Model 12, but I have owned a 2" Airweight M&P 38 for many years
I agree that in this day of the Internet, frame cracking has grown to the level of Urban Legend. While it happens much more often on the alloy framed revolvers than on steel guns, with the millions of airweights sold over the last three quarters of a century, it certainly is not a common problem
And these days the Scandium alloy revolvers have replaced the likes of revolvers like the Model 12. And yes, they are still susceptible to cracking