I'm jaded about my stuttering and achieving fluency. I feel there is no rhyme or reason for fluency. I've stuttered for my whole life except for 3 months in the summer of 2010. (I'm now in my mid-30s.) I felt limitless beyond anything I had ever experienced. I would continually strike up random conversations with strangers to test my limits. I had no limits, I could say anything at anytime to anyone. When my stutter came back I was devastated. I spent hours journaling why I spontaneously became fluent and then lost it. It was to no avail. Eventually, I had to stop chasing it and moved on with my life. But I still miss it :( Keep doing your research and get closure.