I hard cut a video into two segments and deleted the middle. Then I put in a fade to black and rendered out the video. Playing back the rendered file is fine up until the fade to black. After which it doubles the speed of the remainder of the video and has a bunch of black frames appended to the end.
I have not added any speed modifiers and have even tried re-doing the edit with both soft and hard cuts. Scrubbing through the video in the editor does not have this same problem. Everything works fine in the preview just not in the output.