So, as I was working last night I noticed something. I had a video that ended at 14:39:10, which ended on a particular musical note. When I exported that video, that last note was cut off on the .mp4 file. Pondering it later, I thought it might have something to do with the fact that the movie didn't end right on the "whole second" of the timeline, and that the export was shaving those last ten rogue frames off of the final cut to make it an even 14:39, which is why I'd lose the very end of the music.
As the film took over 25 minutes to render, I wasn't keen on repeatedly exporting it to troubleshoot the issue. Am I on the right track, and for future movies should I make sure that they're all an exact number of seconds so that this sort of thing doesn't happen again?