FLV with black at end doesn't appear to reach listenerObject.complete

I had a particular FLV that was not returning to the Flash timeline. On the off chance it was the brief black at the end of the video I reencoded the video trimming off the black and the EventListerner & listenerObject now work. Weird.

I did notice that the playhead seemed to stop on black just a fraction of a centimeter before the end and that dragging the playhead did trigger the gotoAndPlay("frame3")

I guess my question is, what is it about black at the end of an FLV that would cause a stop before the end?