The preview is controlled to some degree by your theme. I would hope that it isn’t displayed that way on a live post, but even if so, I think we can get rid of it.
From what I can see, the content at the top of the page is from the post field called ‘the excerpt’. This is not the full post content as it doesn’t contain your comments as you can see in your screen shot.
In MyCurator you can suppress the saving of this ‘excerpt’ field (doesn’t effect the excerpt in the post). Go to the Admin tab in the Options menu item in MyCurator. Click the “Do Not Save to Excerpt Field in Post” checkbox. Now the excerpt field won’t be saved and so your theme shouldn’t be able to display anything.
This option isn’t ‘retroactive’ so any item previously found by MyCurator still has the excerpt. You can manually remove the excerpt as follows. In the Post Editor, click the Screen Options in gray in the upper right. A list of checkboxes will appear. Click the Excerpt checkbox. Now scroll down until you see a metabox titled Excerpt and delete the contents of the field. After updating, see if the preview looks good.
