When the game took you back to Skyloft after falling, did that particular dialogue with Fi still activate when you tried to pass through the trigger zone(s)? I just started Hero mode and I have been trying to figure out a way to get around the trigger, since it is kind of long. Not sure whether or not this is what happened when you performed the glitch, but it could be faster if the falling from the sky cutscene is shorter than the Fi conversation. Though now that I think about it, it's probably not.
In what I found, Fi still talks to Link, he just keeps falling until he lands on an invisible floor, so the dialogue would have been triggered anyways. It is possible to jump over the railing using my method without crossing the trigger on foot and wihout landing on the railing(which activates the dialogue as well), but I doubt that will get rid of the trigger. And even if it did, I still think listening to the dialogue would be faster. I can't really test this anymore seeing as I saved past that point to look for glitches a bit further on, so maybe you can try it out.
