Amy, I read the recipe, and it wasn’t clear to me, either. It almost sounds like a sentence is missing.
Based on Rose’s methods for Brioche, which I make often (and this comes from the Brioche section), I would guess that one allows the dough to double at room temp, then transfers the bowl to the ‘fridge to chill and ripen. But then it is allowed to nearly triple, which is more rising than the Brioche at that point, so I’m confused, too.
In any event, your stud muffin looks wonderful! So putting it directly into the refrigerator must have been OK. Was it tasty?