Open up a page in VE (any page will do, but a long one like Claude Monet makes this easier to reproduce). While it's loading (ideally when the progress bar is about 1/3 to 1/2 of the way done), click the "read" tab and let the browser load the read version of the page.

If you time things right, you can get a fused page which has both the normal read version of the page and the content-editable version either above or below it (I've also sometimes gotten a page which is blank below the title). I've reproduced this in Firefox 39.0a2, Chrome 42.0.2311.152, and Safari 8.0.6.

Here's an example screenshot showing the "seam" between the read version on top and the VE version below.