Tonight, I exported a video to YouTube and Facebook. I was watching it with my wife when it just stopped about in the middle. I went back to the project in Premiere Pro and noticed that there was a blue bracket ending a shaded area at the top of that video’s timeline exactly where the exported videos, for YouTube and Facebook, ended.
I dragged the bracket to the end of the timeline and exported the video again.
I removed the old videos from Facebook and YouTube and replaced them. They worked fine and played all the way to the end.
What happened? I've never noticed a shaded area ending in a bracket above the timeline before. I don’t want that to happen again.