Considerable discussion of this at the S&W Forum. Looks like a possible metallurgical problem to me. It happens. There was a batch of 624's that had cylinder problems.
That doesn't look good. I'm going to have to go over and read some of that stuff.
But on the plus side, you'ge got the ultimate snub nose.
Possibly.
Looks to me like a weak design.
Is that barrel made of 2 pieces, with an inner and outer sleeve? That looks inadequate for something that must contain pressures on the order of 20,000 to 30,000 psi.
Smiths have always looked flimsy to me. Probably a result of them trying to make them as light as possible.