Man that's so cool, OP! I have a similar memory from class when I was 10-11 years old. I had a moderate stutter and when we would read the book aloud in class in rotation I would eventually get thru my paragraphs but not without a struggle and a few giggles from classmates. One day I was feeling an unexplainable calmness and confidence within me and straight up volunteered to read a whole page when asked. I didn't have a feeling of not having a stutter at all but I read that page as fluently as anyone ever could. Never happened since. There are people who managed to drop the habit and ended up as fluent in the public eye (some famous actors, singers etc.). It could be that they had a similar moment of clarity but instead of it being a one-off it came back and possibly stronger every time. Maybe there was something in that moment and in themselves they were able to disect and distinguish what it was and just run with it. Wish it happened to me too but for me it came and went just like that. Also could be that it was a chance I was "given" but failed to take, what if I kept volunteering to read aloud? Maybe without getting that same feeling of calmness but perhaps that calmness would come, it would only demand some extended cottage and repetition, putting in the work.