I think I have the answer.
You're a diligent and careful re-loader. No mistake should have been made, but the revolver suffered catastrophic damage. You pulled the remaining rounds and they were fine. You could have inspected the round fired in the rifle for excessive pressure, but you probably wouldn't have found anything. The load was not too hot as it was a published load under max. The 125gr cast bullet was not the problem as it shot fine in the rifle and you didn't notice an unusual blast or recoil compared to other rounds.
IMO, the remaining rounds you pulled were fine because they were not overcharged. I believe that you inadvertently double charged only 1 round, perhaps when you switched bullets. It got passed you. An honest mistake and not all that uncommon when a catastrophe happens.
The revolver blew up for a reason and there are no other variables to explain it (not .38 spec crud ring, not seating depth, not loading at or over max published loads, not barrel obstruction, etc).
You sound like a good guy and I'm glad you're ok.