Exporting to Video won't render the whole video

Using File, Export, To video and chosing to stop exporting when last frame is reached. It exports, converts mov to mp4 in Media Encoder but consistently chops off at least half my project in the resulting video. I have no stop(); on the frame where it ends, nothing else notable about that location.

I have experimented with exporitng until 'time elapsed' and that changes nothing.