Scientifically speaking, it shouldn't have happened. But it did. I have a bowl just like that. It's the largest of a set of 'Duralex' nesting bowls made in France. (I had to go to my kitchen to check). They're sort of the French equivalent to Pyrex. I've used all of mine for years in all forms of temperatures, so the only thing that must've occurred is that her husband shot it with a pellet gun from the next room while hiding behind the couch like the d@#k that he is.

Her diamond bracelet scratched the rim.

It appears Rian is correct, though Adelbert has the most simple explanation (Occam's Razor and all that).

who films himself making a recipe ?

I'd out my sausage in her eggs. Meow Meow.

Cheap knock-off pyrex style (not to be confused with real PYREX) can do this spontaneously when the molecular structure is compromised, due to any previous heating and striking.