Exported sequence way longer than storyline

The storyline is a timeline within a project into which footage has been placed to create a sequence. As I understand it, the official name for a timeline in FCP X is 'storyline'.

There are no compound clips on the storyline.

Of the 41 minutes originally placed on the storyline, 27 minutes have been removed in the editing process. The footage was of a 41 minute long conference speech, of which 27 minutes was audience discussion, and was therefore cut out. Thus the original story line was 41 minutes long, but the edited sequence on the story line is 14 minutes long.

The 41 minute long exported video has the edited 14 minute sequence, followed by 27 minutes of plain black. I'm not confusing the Events browser with the storyline. There is a fully-edited sequence which is successfully exported, but with black 'filler' in the exported video, of which no trace can be found on the storyline.

This is an issue with the representation of the timeline in an exported video, rather than a connection between the event browser and the storyline.

Thank you for answering and I hope this additional information is of use to you. The key points are that I'm not confused about how storylines work, or about what the event browser is in comparison, but that there is an exporting issue which I can't understand.

As you can see from this image, the storyline finishes at around the 14 minute mark, but at the bottom of the window, Final Cut is saying the sequence is 41 minutes long. Nor is the scroll bar long enough to indicate there are any stray clips at the 41 minute mark.

Yes, there is a gap clip but it clearly ends at the same time at the rest of the video.

I have also copid and pasted all the clips into a new project, as well as duplicating the project, and this has not resolved the issue.